The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Allen Shearn - One of the best experts on this subject based on the ideXlab platform.
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Loss-of-function mutations in a glutathione S-transferase suppress the Prune-Killer of Prune lethal interaction.
Genetics, 2005Co-Authors: Elayne Provost, Lisa Timmons, Grafton Hersperger, Evelyn Hersperger, Rosa Alcazar, Allen ShearnAbstract:The Prune gene of Drosophila melanogaster is predicted to encode a phosphodiesterase. Null alleles of Prune are viable but cause an eye-color phenotype. The abnormal wing discs gene encodes a nucleoside diphosphate kinase. Killer of Prune is a missense mutation in the abnormal wing discs gene. Although it has no phenotype by itself even when homozygous, Killer of Prune when heterozygous causes lethality in the absence of Prune gene function. A screen for suppressors of transgenic Killer of Prune led to the recovery of three mutations, all of which are in the same gene. As heterozygotes these mutations are dominant suppressors of the Prune-Killer of Prune lethal interaction; as homozygotes these mutations cause early larval lethality and the absence of imaginal discs. These alleles are loss-of-function mutations in CG10065, a gene that is predicted to encode a protein with several zinc finger domains and glutathione S-transferase activity.
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Prune/Killer of Prune: a conditional dominant lethal interaction in Drosophila.
Advances in genetics, 1997Co-Authors: Lisa Timmons, Allen ShearnAbstract:Publisher Summary This chapter discusses the Prune/Killer of Prune (KPN) lethal interaction of Drosophila melanogaster. Immunoblot analysis of Prune protein expression using a polyclonal anti-Prune antibody demonstrated the presence of Prune at all stages of development of Drosophila melanogaster. Maximum accumulation of Prune protein occurred during pupal and adult stages. The smallest quantity of Prune protein relative to total protein was present during the third larval instar stage, the stage during which Prune/Killer of Prune animals die. Several methods are employed in order to determine which tissues in the larvae are sensitive to the Prune/Killer of Prune lethal condition and which of these is responsible for the death of the entire organism. One method is simply to determine the tissues in which both Prune and abnormal wing discs (AWD)/KPN proteins are expressed. Because AWD is expressed in most tissues of the third instar larvae and because very small amounts of Prune protein are required to rescue the Prune/Killer of Prune interaction, any conclusion based on this method would require verification by another method. Another method, the yeast GAL4 targeted expression system, is being employed to reproduce the Prune/Killer of Prune lethal genotype in a subset of tissues in an otherwise viable animal.
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Germline transformation using a Prune cDNA rescues Prune/killer of Prune lethality and the Prune eye color phenotype in Drosophila.
Genetics, 1996Co-Authors: Lisa Timmons, Allen ShearnAbstract:Null mutations in the Prune gene of Drosophila melanogaster result in Prune eye color due to reductions in red pigment accumulation. When one copy of the awd(Killer of Prune) mutant gene is present in a Prune background, the animals die. The cause of Prune/Killer of Prune lethality remains unknown. The genomic region characterized for the Prune locus is transcriptionally active and complex, with multiple and overlapping transcripts. Despite the transcriptional complexity of the genomic region of Prune, accumulated evidence suggests that the Prune locus is small and consists of a single transcription unit, since every Prune allele to date exhibits both Prune eye color and Prune/Killer of Prune lethality. A functional Prune product from a single, full-length cDNA was identified in this study that can rescue both the eye phenotype and Prune/Killer of Prune lethality. The DNA sequences of several mutant Prune alleles along with Western blot analysis of mutant proteins provide convincing evidence that Prune mutations are nulls, and that the cDNA identified in this study encodes the only product of the Prune locus.
Massimo Zollo - One of the best experts on this subject based on the ideXlab platform.
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Prune is crucial for normal brain development and mutated in microcephaly with neurodevelopmental impairment
Brain, 2017Co-Authors: Massimo Zollo, Mustafa Y Ahmed, Veronica Ferrucci, Vincenzo Salpietro, Fatemeh Asadzadeh, Marianeve Carotenuto, Reza Maroofian, Ahmed H Alamri, Royana Singh, Iolanda ScognamiglioAbstract:Prune is a member of the DHH (Asp-His-His) phosphoesterase protein superfamily of molecules important for cell motility, and implicated in cancer progression. Here we investigated multiple families from Oman, India, Iran and Italy with individuals affected by a new autosomal recessive neurodevelopmental and degenerative disorder in which the cardinal features include primary microcephaly and profound global developmental delay. Our genetic studies identified biallelic mutations of Prune1 as responsible. Our functional assays of disease-associated variant alleles revealed impaired microtubule polymerization, as well as cell migration and proliferation properties, of mutant Prune. Additionally, our studies also highlight a potential new role for Prune during microtubule polymerization, which is essential for the cytoskeletal rearrangements that occur during cellular division and proliferation. Together these studies define Prune as a molecule fundamental for normal human cortical development and define cellular and clinical consequences associated with Prune mutation.
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Investigating h-Prune activation of Wnt signalling in breast cancer.
Breast Cancer Research, 2008Co-Authors: Jamie Freeman, Massimo Zollo, Trevor Clive DaleAbstract:We have been investigating a novel link between two independent processes linked to breast cancer: Wnt signalling and h-Prune overexpression. The canonical Wnt signalling pathway was activated in 40% to 60% of human breast cancers through mechanisms that are not understood. Similarly, the phosphodiesterase h-Prune was overexpressed or amplified in 54% of breast cancers and was linked to breast tumour progression through unknown mechanisms. We have shown that overexpression of xenopus Prune induced formation of a secondary axis in a standard assay to identify activators of the Wnt signalling pathway. In HEK293 cells, xenopus Prune overexpression induced a 300-fold increase in Wnt/TCF-dependent transcription. Whilst human Prune does not appear to be able to activate Wnt signalling as potently as its xenopus homologue, it does synergise with other activators of the pathway to increase TCF-dependent transcription. Here we show whether there is a correlation between overexpression of h-Prune and active Wnt signalling in breast cancer, and whether the synergistic responses described are mediated through the enzymatic activity of Prune, or through binding to GSK-3.
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Understanding h-Prune biology in the fight against cancer.
Clinical & experimental metastasis, 2007Co-Authors: Natascia Marino, Massimo ZolloAbstract:The h-Prune protein is a member of the DHH protein superfamily, and its overexpression in breast, colorectal and gastric cancers correlates with depth of invasion and degree of lymph-node metastasis. Taken together with the observation that h-Prune is highly expressed in metastatic breast cancer, this suggests that h-Prune can be used as a marker for the identification of subsets of cancer patients with highly aggressive tumours. H-Prune possesses a phosphodiesterase (cAMP-PDE) activity, and inhibition of PDE activity with dipyridamole suppresses cell motility. H-Prune interacts with nm23-H1, GSK-3β and gelsolin. Although a correlation between an h-Prune PDE activity and cellular motility has been shown, GSK-3β does not affect the PDE activity of h-Prune. Inhibition of the interactions between h-Prune and GSK-3β and nm23-H1 additively suppresses the migration of colon cancer and breast cancer cells, thus suggesting that h-Prune regulates cell motility by two different means of action: through its PDE activity and in its interactions with protein partners. Therefore, the identification of highly specific inhibitors of h-Prune should be useful in the development of drugs to treat cancer metastasis.
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Domain mapping on the human metastasis regulator protein h-Prune reveals a C-terminal dimerization domain
Biochemical Journal, 2007Co-Authors: Sabine Middelhaufe, Livia Garzia, Uta-maria Ohndorf, Barbara Kachholz, Massimo Zollo, Clemens SteegbornAbstract:The human ortholog of the drosophila Prune protein (h-Prune) is an interaction partner and regulator of the metastasis suppressor protein NM23-H1. Studies on a cellular breast cancer model showed that inhibition of the cAMP-specific phosphodiesterase activity of h-Prune can lower the incidence of metastasis formation, suggesting h-Prune inhibition as an exciting approach for therapy of metastatic tumors. H-Prune shows no sequence similarity to known mammalian phosphodiesterases, but instead appears to belong to the DHH (Asp-His-His) superfamily of phosphoesterases. In order to investigate the structure and molecular function of h-Prune, we established its recombinant expression in a bacterial system. Through sequence analysis and limited proteolysis, we could identify domain boundaries and a potential coiled-coil region in a C-terminal cortexillin homology domain. We found that this C-terminal domain mediates h-Prune homodimerization as well as its interaction with NM23-H1. The phosphodiesterase catalytic domain of h-Prune was mapped to the N-terminus and shown to be active even in a monomeric form. Our findings indicate an architecture of h-Prune with two independent active sites and two interaction sites for the assembly of oligomeric signaling complexes.
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glycogen synthase kinase 3 and h Prune regulate cell migration by modulating focal adhesions
Molecular and Cellular Biology, 2006Co-Authors: Tsuyoshi Kobayashi, Massimo Zollo, Shinichiro Hino, Naohide Oue, Toshimasa Asahara, Wataru Yasui, Akira KikuchiAbstract:h-Prune, which has been suggested to be involved in cell migration, was identified as a glycogen synthase kinase 3 (GSK-3)-binding protein. Treatment of cultured cells with GSK-3 inhibitors or small interfering RNA (siRNA) for GSK-3 and h-Prune inhibited their motility. The kinase activity of GSK-3 was required for the interaction of GSK-3 with h-Prune. h-Prune was localized to focal adhesions, and the siRNA for GSK-3 or h-Prune delayed the disassembly of paxillin. The tyrosine phosphorylation of focal adhesion kinase (FAK) and the activation of Rac were suppressed in GSK-3 or h-Prune knocked-down cells. GSK-3 inhibitors suppressed the disassembly of paxillin and the activation of FAK and Rac. Furthermore, h-Prune was highly expressed in colorectal and pancreatic cancers, and the positivity of the h-Prune expression was correlated with tumor invasion. These results suggest that GSK-3 and h-Prune cooperatively regulate the disassembly of focal adhesions to promote cell migration and that h-Prune is useful as a marker for tumor aggressiveness.
Lisa Timmons - One of the best experts on this subject based on the ideXlab platform.
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Loss-of-function mutations in a glutathione S-transferase suppress the Prune-Killer of Prune lethal interaction.
Genetics, 2005Co-Authors: Elayne Provost, Lisa Timmons, Grafton Hersperger, Evelyn Hersperger, Rosa Alcazar, Allen ShearnAbstract:The Prune gene of Drosophila melanogaster is predicted to encode a phosphodiesterase. Null alleles of Prune are viable but cause an eye-color phenotype. The abnormal wing discs gene encodes a nucleoside diphosphate kinase. Killer of Prune is a missense mutation in the abnormal wing discs gene. Although it has no phenotype by itself even when homozygous, Killer of Prune when heterozygous causes lethality in the absence of Prune gene function. A screen for suppressors of transgenic Killer of Prune led to the recovery of three mutations, all of which are in the same gene. As heterozygotes these mutations are dominant suppressors of the Prune-Killer of Prune lethal interaction; as homozygotes these mutations cause early larval lethality and the absence of imaginal discs. These alleles are loss-of-function mutations in CG10065, a gene that is predicted to encode a protein with several zinc finger domains and glutathione S-transferase activity.
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Prune/Killer of Prune: a conditional dominant lethal interaction in Drosophila.
Advances in genetics, 1997Co-Authors: Lisa Timmons, Allen ShearnAbstract:Publisher Summary This chapter discusses the Prune/Killer of Prune (KPN) lethal interaction of Drosophila melanogaster. Immunoblot analysis of Prune protein expression using a polyclonal anti-Prune antibody demonstrated the presence of Prune at all stages of development of Drosophila melanogaster. Maximum accumulation of Prune protein occurred during pupal and adult stages. The smallest quantity of Prune protein relative to total protein was present during the third larval instar stage, the stage during which Prune/Killer of Prune animals die. Several methods are employed in order to determine which tissues in the larvae are sensitive to the Prune/Killer of Prune lethal condition and which of these is responsible for the death of the entire organism. One method is simply to determine the tissues in which both Prune and abnormal wing discs (AWD)/KPN proteins are expressed. Because AWD is expressed in most tissues of the third instar larvae and because very small amounts of Prune protein are required to rescue the Prune/Killer of Prune interaction, any conclusion based on this method would require verification by another method. Another method, the yeast GAL4 targeted expression system, is being employed to reproduce the Prune/Killer of Prune lethal genotype in a subset of tissues in an otherwise viable animal.
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Germline transformation using a Prune cDNA rescues Prune/killer of Prune lethality and the Prune eye color phenotype in Drosophila.
Genetics, 1996Co-Authors: Lisa Timmons, Allen ShearnAbstract:Null mutations in the Prune gene of Drosophila melanogaster result in Prune eye color due to reductions in red pigment accumulation. When one copy of the awd(Killer of Prune) mutant gene is present in a Prune background, the animals die. The cause of Prune/Killer of Prune lethality remains unknown. The genomic region characterized for the Prune locus is transcriptionally active and complex, with multiple and overlapping transcripts. Despite the transcriptional complexity of the genomic region of Prune, accumulated evidence suggests that the Prune locus is small and consists of a single transcription unit, since every Prune allele to date exhibits both Prune eye color and Prune/Killer of Prune lethality. A functional Prune product from a single, full-length cDNA was identified in this study that can rescue both the eye phenotype and Prune/Killer of Prune lethality. The DNA sequences of several mutant Prune alleles along with Western blot analysis of mutant proteins provide convincing evidence that Prune mutations are nulls, and that the cDNA identified in this study encodes the only product of the Prune locus.
Vlad Shchogolev - One of the best experts on this subject based on the ideXlab platform.
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B-matching for spectral clustering
Lecture Notes in Computer Science, 2006Co-Authors: Tony Jebara, Vlad ShchogolevAbstract:We propose preprocessing spectral clustering with b-matching to remove spurious edges in the adjacency graph prior to clustering. B-matching is a generalization of traditional maximum weight matching and is solvable in polynomial time. Instead of a permutation matrix, it produces a binary matrix with rows and columns summing to a positive integer b. The b-matching procedure Prunes graph edges such that the in-degree and out-degree of each node is b, producing a more balanced variant of k-nearest-neighbor. The combinatorial algorithm optimally solves for the maximum weight subgraph and makes subsequent spectral clustering more stable and accurate. Experiments on standard datasets, visualizations, and video data support the use of b-matching to Prune graphs prior to spectral clustering.
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ECML - B-Matching for spectral clustering
Lecture Notes in Computer Science, 2006Co-Authors: Tony Jebara, Vlad ShchogolevAbstract:We propose preprocessing spectral clustering with b-matching to remove spurious edges in the adjacency graph prior to clustering. B-matching is a generalization of traditional maximum weight matching and is solvable in polynomial time. Instead of a permutation matrix, it produces a binary matrix with rows and columns summing to a positive integer b. The b-matching procedure Prunes graph edges such that the in-degree and out-degree of each node is b, producing a more balanced variant of k-nearest-neighbor. The combinatorial algorithm optimally solves for the maximum weight subgraph and makes subsequent spectral clustering more stable and accurate. Experiments on standard datasets, visualizations, and video data support the use of b-matching to Prune graphs prior to spectral clustering.
Tony Jebara - One of the best experts on this subject based on the ideXlab platform.
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B-matching for spectral clustering
Lecture Notes in Computer Science, 2006Co-Authors: Tony Jebara, Vlad ShchogolevAbstract:We propose preprocessing spectral clustering with b-matching to remove spurious edges in the adjacency graph prior to clustering. B-matching is a generalization of traditional maximum weight matching and is solvable in polynomial time. Instead of a permutation matrix, it produces a binary matrix with rows and columns summing to a positive integer b. The b-matching procedure Prunes graph edges such that the in-degree and out-degree of each node is b, producing a more balanced variant of k-nearest-neighbor. The combinatorial algorithm optimally solves for the maximum weight subgraph and makes subsequent spectral clustering more stable and accurate. Experiments on standard datasets, visualizations, and video data support the use of b-matching to Prune graphs prior to spectral clustering.
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ECML - B-Matching for spectral clustering
Lecture Notes in Computer Science, 2006Co-Authors: Tony Jebara, Vlad ShchogolevAbstract:We propose preprocessing spectral clustering with b-matching to remove spurious edges in the adjacency graph prior to clustering. B-matching is a generalization of traditional maximum weight matching and is solvable in polynomial time. Instead of a permutation matrix, it produces a binary matrix with rows and columns summing to a positive integer b. The b-matching procedure Prunes graph edges such that the in-degree and out-degree of each node is b, producing a more balanced variant of k-nearest-neighbor. The combinatorial algorithm optimally solves for the maximum weight subgraph and makes subsequent spectral clustering more stable and accurate. Experiments on standard datasets, visualizations, and video data support the use of b-matching to Prune graphs prior to spectral clustering.
