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Apostolia Guialis - One of the best experts on this subject based on the ideXlab platform.
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Selective interactions of hnRNP M isoforms with the TET proteins TAF15 and TLS/FUS.
Molecular biology reports, 2014Co-Authors: Marija Marko, Michael Leichter, Meropi Patrinou-georgoula, Apostolia GuialisAbstract:The molecular composition of macromolecular assemblies engaged in transcription and splicing influences biogenesis of mRNA transcripts. Preference for one over the other interactive protein partner within those complexes is expected to change the gene expression pattern and to affect subsequent cellular events. We report here the novel and selective associations between RNA-binding proteins, namely the hnRNP M1-4 isoforms—involved in early spliceosome assembly and alternative splicing—and the transcription factors TAF15 and TLS/FUS. In immunoprecipitation studies on HeLa nuclear extracts, TAF15 co-immunoprecipitates preferably with the higher molecular weight hnRNP M3/4 isoforms, opposite to TLS/FUS that associates with the lower molecular weight hnRNP M1/2 species. We demonstrate that these associations can be mediated through direct protein–protein interactions via the amino-termini of the TET proteins, independently of RNA. Finally, we show partial co-localization of TAF15 and TLS/FUS with hnRNP M proteins in HeLa nuclei, supporting the biochemically obtained data. The participation of hnRNP M in an expanding network of protein–protein interactions suggests its important functioning in the coordination of transcriptional and post-transcriptional events.
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selective interactions of hnrnp m isoforms with the tet proteins TAF15 and tls fus
Molecular Biology Reports, 2014Co-Authors: Marija Marko, Michael Leichter, Meropi Patrinougeorgoula, Apostolia GuialisAbstract:The molecular composition of macromolecular assemblies engaged in transcription and splicing influences biogenesis of mRNA transcripts. Preference for one over the other interactive protein partner within those complexes is expected to change the gene expression pattern and to affect subsequent cellular events. We report here the novel and selective associations between RNA-binding proteins, namely the hnRNP M1-4 isoforms—involved in early spliceosome assembly and alternative splicing—and the transcription factors TAF15 and TLS/FUS. In immunoprecipitation studies on HeLa nuclear extracts, TAF15 co-immunoprecipitates preferably with the higher molecular weight hnRNP M3/4 isoforms, opposite to TLS/FUS that associates with the lower molecular weight hnRNP M1/2 species. We demonstrate that these associations can be mediated through direct protein–protein interactions via the amino-termini of the TET proteins, independently of RNA. Finally, we show partial co-localization of TAF15 and TLS/FUS with hnRNP M proteins in HeLa nuclei, supporting the biochemically obtained data. The participation of hnRNP M in an expanding network of protein–protein interactions suggests its important functioning in the coordination of transcriptional and post-transcriptional events.
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Domains involved in TAF15 subcellular localisation: Dependence on cell type and ongoing transcription
Gene, 2012Co-Authors: Marija Marko, Apostolia Guialis, Arsenios Vlassis, Michael LeichterAbstract:Abstract TAF15 (TBP associated factor 15) is a member of the highly conserved TET (also known as FET) protein family of RNA binding proteins (RBP), which comprises in addition FUS (fused in sarcoma, also known as TLS, translocated in liposarcoma) and EWS (Ewing sarcoma protein). The TET proteins are implied to play important roles in the onset of specific tumours, certain forms of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). In this study we identified the domains of TAF15 responsible for its subcellular localisation in human (HeLa) cells and experimentally confirmed the presence of a transportin‐dependent nuclear localisation signal (NLS) at its carboxy-terminus. We demonstrated that additional domains of TAF15 contributed, albeit to a less prominent extent, to its subcellular localisation. In the carboxy-terminus we identified an arginine and glycine rich (RGG) domain, capable of being targeted to stress granules. We, moreover, showed that TAF15 cellular localisation depended on ongoing transcription and that independent domains of TAF15 engaged in nucleolar capping upon transcription inhibition. Finally, we demonstrated that TAF15 localisation was differentially regulated in the HeLa and the neuronal HT22 cell lines and that TAF15 co-localised with a minor subset of RNA granules in the cytoplasm of HT22 cells, supporting a model whereupon TAF15 plays a role in RNA transport and/or local RNA translation.
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A fraction of the transcription factor TAF15 participates in interactions with a subset of the spliceosomal U1 snRNP complex.
Biochimica et biophysica acta, 2011Co-Authors: Michael Leichter, Laszlo Tora, Marija Marko, Vassiliki Ganou, Meropi Patrinou-georgoula, Apostolia GuialisAbstract:Abstract RNA/ssDNA-binding proteins comprise an emerging class of multifunctional proteins with an anticipated role in coupling transcription with RNA processing. We focused here on the highly related transcription factors of the TET sub-class: TLS/FUS, EWS and in particular the least studied member TAF15. An extensive array of immunoprecipitation studies on differentially extracted HeLa nuclei revealed the specific association of TAF15 with the spliceosomal U1 snRNP complex, as deduced by the co-precipitating U1 snRNA, U1-70 K and Sm proteins. Additionally, application of anti-U1 RNP autoantibodies identified TAF15 in the immunoprecipitates. Minor fractions of nuclear TAF15 and U1 snRNP were involved in this association. Pull-down assays using recombinant TAF15 and U1 snRNP-specific proteins (U1-70 K, U1A and U1C) provided in vitro evidence for a direct protein–protein interaction between TAF15 and U1C, which required the N-terminal domain of TAF15. The ability of TAF15 to directly contact RNA, most likely RNA pol II transcripts, was supported by in vivo UV cross-linking studies in the presence of α-amanitin. By all findings, the existence of a functionally discrete subset of U1 snRNP in association with TAF15 was suggested and provided further support for the involvement of U1 snRNP components in early steps of coordinated gene expression.
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Human U1 snRNA forms a new chromatin-associated snRNP with TAF15.
EMBO Reports, 2009Co-Authors: Laure Jobert, Elodie Van Herreweghe, Beáta E. Jády, Tamás Kiss, Natalia Pinzón, Apostolia Guialis, Laszlo ToraAbstract:The U1 small nuclear RNA (snRNA)--in the form of the U1 spliceosomal Sm small nuclear ribonucleoprotein particle (snRNP) that contains seven Sm and three U1-specific RNP proteins-has a crucial function in the recognition and removal of pre-messenger RNA introns. Here, we show that a fraction of human U1 snRNA specifically associates with the nuclear RNA-binding protein TBP-associated factor 15 (TAF15). We show that none of the known protein components of the spliceosomal U1-Sm snRNP interacts with the newly identified U1-TAF15 snRNP. In addition, the U1-TAF15 snRNP tightly associates with chromatin in an RNA-dependent manner and accumulates in nucleolar caps upon transcriptional inhibition. The Sm-binding motif of U1 snRNA is essential for the biogenesis of both U1-Sm and U1-TAF15 snRNPs, suggesting that the U1-TAF15 particle is produced by remodelling of the U1-Sm snRNP. A demonstration that human U1 snRNA forms at least two structurally distinct snRNPs supports the idea that the U1 snRNA has many nuclear functions.
Laszlo Tora - One of the best experts on this subject based on the ideXlab platform.
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Transcription of Nearly All Yeast RNA Polymerase II-Transcribed Genes Is Dependent on Transcription Factor TFIID.
Molecular Cell, 2017Co-Authors: Linda Warfield, Laszlo Tora, Tiago Baptista, Srinivas Ramachandran, Didier Devys, Steven HahnAbstract:Previous studies suggested that expression of most yeast mRNAs is dominated by either transcription factor TFIID or SAGA. We re-examined the role of TFIID by rapid depletion of S. cerevisiae TFIID subunits and measurement of changes in nascent transcription. We find that transcription of nearly all mRNAs is strongly dependent on TFIID function. Degron-dependent depletion of Taf1, Taf2, Taf7, Taf11, and Taf13 showed similar transcription decreases for genes in the Taf1-depleted, Taf1-enriched, TATA-containing, and TATA-less gene classes. The magnitude of TFIID dependence varies with growth conditions, although this variation is similar genome-wide. Many studies have suggested differences in gene-regulatory mechanisms between TATA and TATA-less genes, and these differences have been attributed in part to differential dependence on SAGA or TFIID. Our work indicates that TFIID participates in expression of nearly all yeast mRNAs and that differences in regulation between these two gene categories is due to other properties.
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The architecture of human general transcription factor TFIID core complex
Nature, 2013Co-Authors: Christoph Bieniossek, Gabor Papai, Christiane Schaffitzel, Frederic Garzoni, Maxime Chaillet, Elisabeth Scheer, Petros Papadopoulos, Laszlo Tora, Patrick Schultz, Imre BergerAbstract:The structures of three distinct human transcription factor IID (TFIID) protein assemblies are solved using cryo-electron microscopy; by incorporating TAF8 and TAF10, the key structural changes that remodel TFIID during assembly are determined, particularly the transition from a symmetric core-TFIID to an asymmetric holo-complex. TFIID is the first general transcription factor to bind gene promoters prior to gene transcription by RNA polymerase II, triggering pre-initiation complex formation and functioning as a coactivator. TFIID is a large multiprotein complex composed of TATA-box-binding protein (TBP) and TBP-associated factors (TAFs). Imre Berger and colleagues now determine structures of three distinct human TFIID protein assemblies using cryo-electron microscopy. In their model for step-wise assembly of the complex, the transition from a symmetric core TFIID to an asymmetric holo-complex occurs upon binding of TAF8 and TAF10, which induces major conformational changes. The initiation of gene transcription by RNA polymerase II is regulated by a plethora of proteins in human cells. The first general transcription factor to bind gene promoters is transcription factor IID (TFIID). TFIID triggers pre-initiation complex formation, functions as a coactivator by interacting with transcriptional activators and reads epigenetic marks^ 1 , 2 , 3 . TFIID is a megadalton-sized multiprotein complex composed of TATA-box-binding protein (TBP) and 13 TBP-associated factors (TAFs)^ 3 . Despite its crucial role, the detailed architecture and assembly mechanism of TFIID remain elusive. Histone fold domains are prevalent in TAFs, and histone-like tetramer and octamer structures have been proposed in TFIID^ 4 , 5 , 6 . A functional core-TFIID subcomplex was revealed in Drosophila nuclei, consisting of a subset of TAFs (TAF4, TAF5, TAF6, TAF9 and TAF12)^ 7 . These core subunits are thought to be present in two copies in holo-TFIID, in contrast to TBP and other TAFs that are present in a single copy^ 8 , conveying a transition from symmetry to asymmetry in the TFIID assembly pathway. Here we present the structure of human core-TFIID determined by cryo-electron microscopy at 11.6 Å resolution. Our structure reveals a two-fold symmetric, interlaced architecture, with pronounced protrusions, that accommodates all conserved structural features of the TAFs including the histone folds. We further demonstrate that binding of one TAF8–TAF10 complex breaks the original symmetry of core-TFIID. We propose that the resulting asymmetric structure serves as a functional scaffold to nucleate holo-TFIID assembly, by accreting one copy each of the remaining TAFs and TBP.
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The architecture of human general transcription factor TFIID core complex
Nature, 2013Co-Authors: Christoph Bieniossek, Gabor Papai, Christiane Schaffitzel, Frederic Garzoni, Maxime Chaillet, Elisabeth Scheer, Petros Papadopoulos, Laszlo Tora, Patrick Schultz, Imre BergerAbstract:The initiation of gene transcription by RNA polymerase II is regulated by a plethora of proteins in human cells. The first general transcription factor to bind gene promoters is transcription factor IID (TFIID). TFIID triggers pre-initiation complex formation, functions as a coactivator by interacting with transcriptional activators and reads epigenetic marks. TFIID is a megadalton-sized multiprotein complex composed of TATA-box-binding protein (TBP) and 13 TBP-associated factors (TAFs). Despite its crucial role, the detailed architecture and assembly mechanism of TFIID remain elusive. Histone fold domains are prevalent in TAFs, and histone-like tetramer and octamer structures have been proposed in TFIID. A functional core-TFIID subcomplex was revealed in Drosophila nuclei, consisting of a subset of TAFs (TAF4, TAF5, TAF6, TAF9 and TAF12). These core subunits are thought to be present in two copies in holo-TFIID, in contrast to TBP and other TAFs that are present in a single copy, conveying a transition from symmetry to asymmetry in the TFIID assembly pathway. Here we present the structure of human core-TFIID determined by cryo-electron microscopy at 11.6 A resolution. Our structure reveals a two-fold symmetric, interlaced architecture, with pronounced protrusions, that accommodates all conserved structural features of the TAFs including the histone folds. We further demonstrate that binding of one TAF8-TAF10 complex breaks the original symmetry of core-TFIID. We propose that the resulting asymmetric structure serves as a functional scaffold to nucleate holo-TFIID assembly, by accreting one copy each of the remaining TAFs and TBP.
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A fraction of the transcription factor TAF15 participates in interactions with a subset of the spliceosomal U1 snRNP complex.
Biochimica et biophysica acta, 2011Co-Authors: Michael Leichter, Laszlo Tora, Marija Marko, Vassiliki Ganou, Meropi Patrinou-georgoula, Apostolia GuialisAbstract:Abstract RNA/ssDNA-binding proteins comprise an emerging class of multifunctional proteins with an anticipated role in coupling transcription with RNA processing. We focused here on the highly related transcription factors of the TET sub-class: TLS/FUS, EWS and in particular the least studied member TAF15. An extensive array of immunoprecipitation studies on differentially extracted HeLa nuclei revealed the specific association of TAF15 with the spliceosomal U1 snRNP complex, as deduced by the co-precipitating U1 snRNA, U1-70 K and Sm proteins. Additionally, application of anti-U1 RNP autoantibodies identified TAF15 in the immunoprecipitates. Minor fractions of nuclear TAF15 and U1 snRNP were involved in this association. Pull-down assays using recombinant TAF15 and U1 snRNP-specific proteins (U1-70 K, U1A and U1C) provided in vitro evidence for a direct protein–protein interaction between TAF15 and U1C, which required the N-terminal domain of TAF15. The ability of TAF15 to directly contact RNA, most likely RNA pol II transcripts, was supported by in vivo UV cross-linking studies in the presence of α-amanitin. By all findings, the existence of a functionally discrete subset of U1 snRNP in association with TAF15 was suggested and provided further support for the involvement of U1 snRNP components in early steps of coordinated gene expression.
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Human U1 snRNA forms a new chromatin-associated snRNP with TAF15.
EMBO Reports, 2009Co-Authors: Laure Jobert, Elodie Van Herreweghe, Beáta E. Jády, Tamás Kiss, Natalia Pinzón, Apostolia Guialis, Laszlo ToraAbstract:The U1 small nuclear RNA (snRNA)--in the form of the U1 spliceosomal Sm small nuclear ribonucleoprotein particle (snRNP) that contains seven Sm and three U1-specific RNP proteins-has a crucial function in the recognition and removal of pre-messenger RNA introns. Here, we show that a fraction of human U1 snRNA specifically associates with the nuclear RNA-binding protein TBP-associated factor 15 (TAF15). We show that none of the known protein components of the spliceosomal U1-Sm snRNP interacts with the newly identified U1-TAF15 snRNP. In addition, the U1-TAF15 snRNP tightly associates with chromatin in an RNA-dependent manner and accumulates in nucleolar caps upon transcriptional inhibition. The Sm-binding motif of U1 snRNA is essential for the biogenesis of both U1-Sm and U1-TAF15 snRNPs, suggesting that the U1-TAF15 particle is produced by remodelling of the U1-Sm snRNP. A demonstration that human U1 snRNA forms at least two structurally distinct snRNPs supports the idea that the U1 snRNA has many nuclear functions.
Marija Marko - One of the best experts on this subject based on the ideXlab platform.
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Selective interactions of hnRNP M isoforms with the TET proteins TAF15 and TLS/FUS.
Molecular biology reports, 2014Co-Authors: Marija Marko, Michael Leichter, Meropi Patrinou-georgoula, Apostolia GuialisAbstract:The molecular composition of macromolecular assemblies engaged in transcription and splicing influences biogenesis of mRNA transcripts. Preference for one over the other interactive protein partner within those complexes is expected to change the gene expression pattern and to affect subsequent cellular events. We report here the novel and selective associations between RNA-binding proteins, namely the hnRNP M1-4 isoforms—involved in early spliceosome assembly and alternative splicing—and the transcription factors TAF15 and TLS/FUS. In immunoprecipitation studies on HeLa nuclear extracts, TAF15 co-immunoprecipitates preferably with the higher molecular weight hnRNP M3/4 isoforms, opposite to TLS/FUS that associates with the lower molecular weight hnRNP M1/2 species. We demonstrate that these associations can be mediated through direct protein–protein interactions via the amino-termini of the TET proteins, independently of RNA. Finally, we show partial co-localization of TAF15 and TLS/FUS with hnRNP M proteins in HeLa nuclei, supporting the biochemically obtained data. The participation of hnRNP M in an expanding network of protein–protein interactions suggests its important functioning in the coordination of transcriptional and post-transcriptional events.
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selective interactions of hnrnp m isoforms with the tet proteins TAF15 and tls fus
Molecular Biology Reports, 2014Co-Authors: Marija Marko, Michael Leichter, Meropi Patrinougeorgoula, Apostolia GuialisAbstract:The molecular composition of macromolecular assemblies engaged in transcription and splicing influences biogenesis of mRNA transcripts. Preference for one over the other interactive protein partner within those complexes is expected to change the gene expression pattern and to affect subsequent cellular events. We report here the novel and selective associations between RNA-binding proteins, namely the hnRNP M1-4 isoforms—involved in early spliceosome assembly and alternative splicing—and the transcription factors TAF15 and TLS/FUS. In immunoprecipitation studies on HeLa nuclear extracts, TAF15 co-immunoprecipitates preferably with the higher molecular weight hnRNP M3/4 isoforms, opposite to TLS/FUS that associates with the lower molecular weight hnRNP M1/2 species. We demonstrate that these associations can be mediated through direct protein–protein interactions via the amino-termini of the TET proteins, independently of RNA. Finally, we show partial co-localization of TAF15 and TLS/FUS with hnRNP M proteins in HeLa nuclei, supporting the biochemically obtained data. The participation of hnRNP M in an expanding network of protein–protein interactions suggests its important functioning in the coordination of transcriptional and post-transcriptional events.
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Domains involved in TAF15 subcellular localisation: Dependence on cell type and ongoing transcription
Gene, 2012Co-Authors: Marija Marko, Apostolia Guialis, Arsenios Vlassis, Michael LeichterAbstract:Abstract TAF15 (TBP associated factor 15) is a member of the highly conserved TET (also known as FET) protein family of RNA binding proteins (RBP), which comprises in addition FUS (fused in sarcoma, also known as TLS, translocated in liposarcoma) and EWS (Ewing sarcoma protein). The TET proteins are implied to play important roles in the onset of specific tumours, certain forms of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). In this study we identified the domains of TAF15 responsible for its subcellular localisation in human (HeLa) cells and experimentally confirmed the presence of a transportin‐dependent nuclear localisation signal (NLS) at its carboxy-terminus. We demonstrated that additional domains of TAF15 contributed, albeit to a less prominent extent, to its subcellular localisation. In the carboxy-terminus we identified an arginine and glycine rich (RGG) domain, capable of being targeted to stress granules. We, moreover, showed that TAF15 cellular localisation depended on ongoing transcription and that independent domains of TAF15 engaged in nucleolar capping upon transcription inhibition. Finally, we demonstrated that TAF15 localisation was differentially regulated in the HeLa and the neuronal HT22 cell lines and that TAF15 co-localised with a minor subset of RNA granules in the cytoplasm of HT22 cells, supporting a model whereupon TAF15 plays a role in RNA transport and/or local RNA translation.
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A fraction of the transcription factor TAF15 participates in interactions with a subset of the spliceosomal U1 snRNP complex.
Biochimica et biophysica acta, 2011Co-Authors: Michael Leichter, Laszlo Tora, Marija Marko, Vassiliki Ganou, Meropi Patrinou-georgoula, Apostolia GuialisAbstract:Abstract RNA/ssDNA-binding proteins comprise an emerging class of multifunctional proteins with an anticipated role in coupling transcription with RNA processing. We focused here on the highly related transcription factors of the TET sub-class: TLS/FUS, EWS and in particular the least studied member TAF15. An extensive array of immunoprecipitation studies on differentially extracted HeLa nuclei revealed the specific association of TAF15 with the spliceosomal U1 snRNP complex, as deduced by the co-precipitating U1 snRNA, U1-70 K and Sm proteins. Additionally, application of anti-U1 RNP autoantibodies identified TAF15 in the immunoprecipitates. Minor fractions of nuclear TAF15 and U1 snRNP were involved in this association. Pull-down assays using recombinant TAF15 and U1 snRNP-specific proteins (U1-70 K, U1A and U1C) provided in vitro evidence for a direct protein–protein interaction between TAF15 and U1C, which required the N-terminal domain of TAF15. The ability of TAF15 to directly contact RNA, most likely RNA pol II transcripts, was supported by in vivo UV cross-linking studies in the presence of α-amanitin. By all findings, the existence of a functionally discrete subset of U1 snRNP in association with TAF15 was suggested and provided further support for the involvement of U1 snRNP components in early steps of coordinated gene expression.
Michael Leichter - One of the best experts on this subject based on the ideXlab platform.
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Selective interactions of hnRNP M isoforms with the TET proteins TAF15 and TLS/FUS.
Molecular biology reports, 2014Co-Authors: Marija Marko, Michael Leichter, Meropi Patrinou-georgoula, Apostolia GuialisAbstract:The molecular composition of macromolecular assemblies engaged in transcription and splicing influences biogenesis of mRNA transcripts. Preference for one over the other interactive protein partner within those complexes is expected to change the gene expression pattern and to affect subsequent cellular events. We report here the novel and selective associations between RNA-binding proteins, namely the hnRNP M1-4 isoforms—involved in early spliceosome assembly and alternative splicing—and the transcription factors TAF15 and TLS/FUS. In immunoprecipitation studies on HeLa nuclear extracts, TAF15 co-immunoprecipitates preferably with the higher molecular weight hnRNP M3/4 isoforms, opposite to TLS/FUS that associates with the lower molecular weight hnRNP M1/2 species. We demonstrate that these associations can be mediated through direct protein–protein interactions via the amino-termini of the TET proteins, independently of RNA. Finally, we show partial co-localization of TAF15 and TLS/FUS with hnRNP M proteins in HeLa nuclei, supporting the biochemically obtained data. The participation of hnRNP M in an expanding network of protein–protein interactions suggests its important functioning in the coordination of transcriptional and post-transcriptional events.
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selective interactions of hnrnp m isoforms with the tet proteins TAF15 and tls fus
Molecular Biology Reports, 2014Co-Authors: Marija Marko, Michael Leichter, Meropi Patrinougeorgoula, Apostolia GuialisAbstract:The molecular composition of macromolecular assemblies engaged in transcription and splicing influences biogenesis of mRNA transcripts. Preference for one over the other interactive protein partner within those complexes is expected to change the gene expression pattern and to affect subsequent cellular events. We report here the novel and selective associations between RNA-binding proteins, namely the hnRNP M1-4 isoforms—involved in early spliceosome assembly and alternative splicing—and the transcription factors TAF15 and TLS/FUS. In immunoprecipitation studies on HeLa nuclear extracts, TAF15 co-immunoprecipitates preferably with the higher molecular weight hnRNP M3/4 isoforms, opposite to TLS/FUS that associates with the lower molecular weight hnRNP M1/2 species. We demonstrate that these associations can be mediated through direct protein–protein interactions via the amino-termini of the TET proteins, independently of RNA. Finally, we show partial co-localization of TAF15 and TLS/FUS with hnRNP M proteins in HeLa nuclei, supporting the biochemically obtained data. The participation of hnRNP M in an expanding network of protein–protein interactions suggests its important functioning in the coordination of transcriptional and post-transcriptional events.
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Domains involved in TAF15 subcellular localisation: Dependence on cell type and ongoing transcription
Gene, 2012Co-Authors: Marija Marko, Apostolia Guialis, Arsenios Vlassis, Michael LeichterAbstract:Abstract TAF15 (TBP associated factor 15) is a member of the highly conserved TET (also known as FET) protein family of RNA binding proteins (RBP), which comprises in addition FUS (fused in sarcoma, also known as TLS, translocated in liposarcoma) and EWS (Ewing sarcoma protein). The TET proteins are implied to play important roles in the onset of specific tumours, certain forms of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). In this study we identified the domains of TAF15 responsible for its subcellular localisation in human (HeLa) cells and experimentally confirmed the presence of a transportin‐dependent nuclear localisation signal (NLS) at its carboxy-terminus. We demonstrated that additional domains of TAF15 contributed, albeit to a less prominent extent, to its subcellular localisation. In the carboxy-terminus we identified an arginine and glycine rich (RGG) domain, capable of being targeted to stress granules. We, moreover, showed that TAF15 cellular localisation depended on ongoing transcription and that independent domains of TAF15 engaged in nucleolar capping upon transcription inhibition. Finally, we demonstrated that TAF15 localisation was differentially regulated in the HeLa and the neuronal HT22 cell lines and that TAF15 co-localised with a minor subset of RNA granules in the cytoplasm of HT22 cells, supporting a model whereupon TAF15 plays a role in RNA transport and/or local RNA translation.
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A fraction of the transcription factor TAF15 participates in interactions with a subset of the spliceosomal U1 snRNP complex.
Biochimica et biophysica acta, 2011Co-Authors: Michael Leichter, Laszlo Tora, Marija Marko, Vassiliki Ganou, Meropi Patrinou-georgoula, Apostolia GuialisAbstract:Abstract RNA/ssDNA-binding proteins comprise an emerging class of multifunctional proteins with an anticipated role in coupling transcription with RNA processing. We focused here on the highly related transcription factors of the TET sub-class: TLS/FUS, EWS and in particular the least studied member TAF15. An extensive array of immunoprecipitation studies on differentially extracted HeLa nuclei revealed the specific association of TAF15 with the spliceosomal U1 snRNP complex, as deduced by the co-precipitating U1 snRNA, U1-70 K and Sm proteins. Additionally, application of anti-U1 RNP autoantibodies identified TAF15 in the immunoprecipitates. Minor fractions of nuclear TAF15 and U1 snRNP were involved in this association. Pull-down assays using recombinant TAF15 and U1 snRNP-specific proteins (U1-70 K, U1A and U1C) provided in vitro evidence for a direct protein–protein interaction between TAF15 and U1C, which required the N-terminal domain of TAF15. The ability of TAF15 to directly contact RNA, most likely RNA pol II transcripts, was supported by in vivo UV cross-linking studies in the presence of α-amanitin. By all findings, the existence of a functionally discrete subset of U1 snRNP in association with TAF15 was suggested and provided further support for the involvement of U1 snRNP components in early steps of coordinated gene expression.
Laure Jobert - One of the best experts on this subject based on the ideXlab platform.
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TAF15 is important for cellular proliferation and regulates the expression of a subset of cell cycle genes through miRNAs
Oncogene, 2013Co-Authors: M Ballarino, Laure Jobert, D Dembélé, P De La Grange, D Auboeuf, L ToraAbstract:TAF15 (formerly TAFII68) is a member of the FET (FUS, EWS, TAF15) family of RNA- and DNA-binding proteins whose genes are frequently translocated in sarcomas. By performing global gene expression profiling, we found that TAF15 knockdown affects the expression of a large subset of genes, of which a significant percentage is involved in cell cycle and cell death. In agreement, TAF15 depletion had a growth-inhibitory effect and resulted in increased apoptosis. Among the TAF15-regulated genes, targets of microRNAs (miRNAs) generated from the onco-miR-17 locus were overrepresented, with CDKN1A/p21 being the top miRNAs-targeted gene. Interestingly, the levels of onco-miR-17 locus coded miRNAs (miR-17-5p and miR-20a) were decreased upon TAF15 depletion and shown to affect the post-transcriptional regulation of TAF15-dependent genes, such as CDKN1A/p21 . Thus, our results demonstrate that TAF15 is required to regulate gene expression of cell cycle regulatory genes post-transcriptionally through a pathway involving miRNAs. The findings that high TAF15 levels are needed for rapid cellular proliferation and that endogenous TAF15 levels decrease during differentiation strongly suggest that TAF15 is a key regulator of maintaining a highly proliferative rate of cellular homeostasis.
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TAF15 is important for cellular proliferation and regulates the expression of a subset of cell cycle genes through miRNAs.
Oncogene, 2012Co-Authors: M Ballarino, Laure Jobert, D Dembélé, P De La Grange, D Auboeuf, L ToraAbstract:TAF15 (formerly TAFII68) is a member of the FET (FUS, EWS, TAF15) family of RNA- and DNA-binding proteins whose genes are frequently translocated in sarcomas. By performing global gene expression profiling, we found that TAF15 knockdown affects the expression of a large subset of genes, of which a significant percentage is involved in cell cycle and cell death. In agreement, TAF15 depletion had a growth-inhibitory effect and resulted in increased apoptosis. Among the TAF15-regulated genes, targets of microRNAs (miRNAs) generated from the onco-miR-17 locus were overrepresented, with CDKN1A/p21 being the top miRNAs-targeted gene. Interestingly, the levels of onco-miR-17 locus coded miRNAs (miR-17-5p and miR-20a) were decreased upon TAF15 depletion and shown to affect the post-transcriptional regulation of TAF15-dependent genes, such as CDKN1A/p21. Thus, our results demonstrate that TAF15 is required to regulate gene expression of cell cycle regulatory genes post-transcriptionally through a pathway involving miRNAs. The findings that high TAF15 levels are needed for rapid cellular proliferation and that endogenous TAF15 levels decrease during differentiation strongly suggest that TAF15 is a key regulator of maintaining a highly proliferative rate of cellular homeostasis.Oncogene advance online publication, 5 November 2012; doi:10.1038/onc.2012.490.
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Human U1 snRNA forms a new chromatin-associated snRNP with TAF15.
EMBO Reports, 2009Co-Authors: Laure Jobert, Elodie Van Herreweghe, Beáta E. Jády, Tamás Kiss, Natalia Pinzón, Apostolia Guialis, Laszlo ToraAbstract:The U1 small nuclear RNA (snRNA)--in the form of the U1 spliceosomal Sm small nuclear ribonucleoprotein particle (snRNP) that contains seven Sm and three U1-specific RNP proteins-has a crucial function in the recognition and removal of pre-messenger RNA introns. Here, we show that a fraction of human U1 snRNA specifically associates with the nuclear RNA-binding protein TBP-associated factor 15 (TAF15). We show that none of the known protein components of the spliceosomal U1-Sm snRNP interacts with the newly identified U1-TAF15 snRNP. In addition, the U1-TAF15 snRNP tightly associates with chromatin in an RNA-dependent manner and accumulates in nucleolar caps upon transcriptional inhibition. The Sm-binding motif of U1 snRNA is essential for the biogenesis of both U1-Sm and U1-TAF15 snRNPs, suggesting that the U1-TAF15 particle is produced by remodelling of the U1-Sm snRNP. A demonstration that human U1 snRNA forms at least two structurally distinct snRNPs supports the idea that the U1 snRNA has many nuclear functions.
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PRMT1 mediated methylation of TAF15 is required for its positive gene regulatory function.
Experimental Cell Research, 2009Co-Authors: Laure Jobert, Manuela Argentini, Laszlo ToraAbstract:TAF15 (formerly TAF(II)68) is a nuclear RNA-binding protein that is associated with a distinct population of TFIID and RNA polymerase II complexes. TAF15 harbours an N-terminal activation domain, an RNA recognition motif (RRM) and many Arg-Gly-Gly (RGG) repeats at its C-terminal end. The N-terminus of TAF15 serves as an essential transforming domain in the fusion oncoprotein created by chromosomal translocation in certain human chondrosarcomas. Post-transcriptional modifications (PTMs) of proteins are known to regulate their activity, however, nothing is known on how PTMs affect TAF15 function. Here we demonstrate that endogenous human TAF15 is methylated in vivo at its numerous RGG repeats. Furthermore, we identify protein arginine N-methyltransferase 1 (PRMT1) as a TAF15 interactor and the major PRMT responsible for its methylation. In addition, the RGG repeat-containing C-terminus of TAF15 is responsible for the shuttling between the nucleus and the cytoplasm and the methylation of RGG repeats affects the subcellular localization of TAF15. The methylation of TAF15 by PRMT1 is required for the ability of TAF15 to positively regulate the expression of the studied endogenous TAF15-target genes. Our findings demonstrate that arginine methylation of TAF15 by PRMT1 is a crucial event determining its proper localization and gene regulatory function.
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analysis of the function of human TAF15 in the regulation of gene expression
2007Co-Authors: Laure JobertAbstract:TAF15 (TBP-associated factor 15) forms with EWS (Ewing sarcoma) and TLS (translocated in liposarcoma) the TET protein family, whose genes are frequently translocated in human sarcomas. TAF15 has been identified on the basis of its association with a subpopulation of the general transcription factor TFIID and RNA polymerase II. We found by gene expression profiling that about 7. 5% of the genes were misregulated upon TAF15 knockdown. A detailed analysis of certain TAF15-regulated genes showed that TAF15 acts at the transcriptional level and is recruited on the transcripts of its target genes. Most importantly, TAF15 can form a novel complex with the spliceosomal small nuclear U1 RNA (U1 snRNA) that is distinct from the well-characterized small nuclear ribonucleoprotein U1 particle. Since TAF15 binds both the U1 snRNA and its target transcripts and also controls transcription of a specific set of genes, TAF15 may participate in the coupling of transcription and splicing on certain genes.
