The Experts below are selected from a list of 112320 Experts worldwide ranked by ideXlab platform
Jacques Cote - One of the best experts on this subject based on the ideXlab platform.
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eaf1 is the platform for nua4 molecular assembly that evolutionarily links chromatin acetylation to atp dependent exchange of Histone h2a variants
Molecular and Cellular Biology, 2008Co-Authors: Andreanne Auger, Luc Galarneau, Mohammed Altaf, Amine Nourani, Yannick Doyon, Rhea T Utley, Dominique Cronier, Stephane Allard, Jacques CoteAbstract:Eaf1 (for Esa1-associated factor 1) and Eaf2 have been identified as stable subunits of NuA4, a yeast Histone H4/H2A acetyltransferase complex implicated in gene regulation and DNA repair. While both SWI3-ADA2-N-CoR-TF IIIB domain-containing proteins are required for normal cell cycle progression, their depletion does not affect the global Esa1-dependent acetylation of Histones. In contrast to all other subunits, Eaf1 is found exclusively associated with the NuA4 complex in vivo. It serves as a platform that coordinates the assembly of functional groups of subunits into the native NuA4 complex. Eaf1 shows structural similarities with human p400/Domino, a subunit of the NuA4-related TIP60 complex. On the other hand, p400 also possesses an SWI2/SNF2 family ATPase domain that is absent from the yeast NuA4 complex. This domain is highly related to the yeast Swr1 protein, which is responsible for the incorporation of Histone variant H2AZ in chromatin. Since all of the components of the TIP60 complex are homologous to SWR1 or NuA4 subunits, we proposed that the human complex corresponds to a physical merge of two yeast complexes. p400 function in TIP60 then would be accomplished in yeast by cooperation between SWR1 and NuA4. In agreement with such a model, NuA4 and SWR1 mutants show strong genetic interactions, NuA4 affects Histone H2AZ incorporation/acetylation in vivo, and both preset the PHO5 promoter for activation. Interestingly, the expression of a chimeric Eaf1-Swr1 protein recreates a single human-like complex in yeast cells. Our results identified the key central subunit for the structure and functions of the NuA4 Histone acetyltransferase complex and functionally linked this activity with the Histone variant H2AZ from yeast to human cells.
Jan Van Oostrum - One of the best experts on this subject based on the ideXlab platform.
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characterization of Histone h2a and h2b variants and their post translational modifications by mass spectrometry
Molecular & Cellular Proteomics, 2006Co-Authors: Debora Bonenfant, Michele Coulot, Harry Towbin, Patrick Schindler, Jan Van OostrumAbstract:The nucleosome, the fundamental structural unit of chromatin, contains an octamer of core Histones H3, H4, H2A, and H2B. Incorporation of Histone variants alters the functional properties of chromatin. To understand the global dynamics of chromatin structure and function, analysis of Histone variants incorporated into the nucleosome and their covalent modifications is required. Here we report the first global mass spectrometric analysis of Histone H2A and H2B variants derived from Jurkat cells. A combination of mass spectrometric techniques, HPLC separations, and enzymatic digestions using endoproteinase Glu-C, endoproteinase Arg-C, and trypsin were used to identify Histone H2A and H2B subtypes and their modifications. We identified nine Histone H2A and 11 Histone H2B subtypes, among them proteins that only had been postulated at the gene level. The two main H2A variants, H2AO and H2AC, as well as H2AL were either acetylated at Lys-5 or phosphorylated at Ser-1. For the replacement Histone H2AZ, acetylation at Lys-4 and Lys-7 was found. The main Histone H2B variant, H2BA, was acetylated at Lys-12, -15, and -20. The analysis of core Histone subtypes with their modifications provides a first step toward an understanding of the functional significance of the diversity of Histone structures.
Andreanne Auger - One of the best experts on this subject based on the ideXlab platform.
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eaf1 is the platform for nua4 molecular assembly that evolutionarily links chromatin acetylation to atp dependent exchange of Histone h2a variants
Molecular and Cellular Biology, 2008Co-Authors: Andreanne Auger, Luc Galarneau, Mohammed Altaf, Amine Nourani, Yannick Doyon, Rhea T Utley, Dominique Cronier, Stephane Allard, Jacques CoteAbstract:Eaf1 (for Esa1-associated factor 1) and Eaf2 have been identified as stable subunits of NuA4, a yeast Histone H4/H2A acetyltransferase complex implicated in gene regulation and DNA repair. While both SWI3-ADA2-N-CoR-TF IIIB domain-containing proteins are required for normal cell cycle progression, their depletion does not affect the global Esa1-dependent acetylation of Histones. In contrast to all other subunits, Eaf1 is found exclusively associated with the NuA4 complex in vivo. It serves as a platform that coordinates the assembly of functional groups of subunits into the native NuA4 complex. Eaf1 shows structural similarities with human p400/Domino, a subunit of the NuA4-related TIP60 complex. On the other hand, p400 also possesses an SWI2/SNF2 family ATPase domain that is absent from the yeast NuA4 complex. This domain is highly related to the yeast Swr1 protein, which is responsible for the incorporation of Histone variant H2AZ in chromatin. Since all of the components of the TIP60 complex are homologous to SWR1 or NuA4 subunits, we proposed that the human complex corresponds to a physical merge of two yeast complexes. p400 function in TIP60 then would be accomplished in yeast by cooperation between SWR1 and NuA4. In agreement with such a model, NuA4 and SWR1 mutants show strong genetic interactions, NuA4 affects Histone H2AZ incorporation/acetylation in vivo, and both preset the PHO5 promoter for activation. Interestingly, the expression of a chimeric Eaf1-Swr1 protein recreates a single human-like complex in yeast cells. Our results identified the key central subunit for the structure and functions of the NuA4 Histone acetyltransferase complex and functionally linked this activity with the Histone variant H2AZ from yeast to human cells.
Joseph Landry - One of the best experts on this subject based on the ideXlab platform.
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atp driven exchange of Histone H2AZ variant catalyzed by swr1 chromatin remodeling complex
Science, 2004Co-Authors: Gaku Mizuguchi, Xuetong She, Joseph LandryAbstract:The conserved Histone variant H2AZ has an important role in the regulation of gene expression and the establishment of a buffer to the spread of silent heterochromatin. How Histone variants such as H2AZ are incorporated into nucleosomes has been obscure. We have found that Swr1, a Swi2/Snf2-related adenosine triphosphatase, is the catalytic core of a multisubunit, Histone-variant exchanger that efficiently replaces conventional Histone H2A with Histone H2AZ in nucleosome arrays. Swr1 is required for the deposition of Histone H2AZ at specific chromosome locations in vivo, and Swr1 and H2AZ commonly regulate a subset of yeast genes. These findings define a previously unknown role for the adenosine triphosphate-dependent chromatin remodeling machinery.
Debora Bonenfant - One of the best experts on this subject based on the ideXlab platform.
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characterization of Histone h2a and h2b variants and their post translational modifications by mass spectrometry
Molecular & Cellular Proteomics, 2006Co-Authors: Debora Bonenfant, Michele Coulot, Harry Towbin, Patrick Schindler, Jan Van OostrumAbstract:The nucleosome, the fundamental structural unit of chromatin, contains an octamer of core Histones H3, H4, H2A, and H2B. Incorporation of Histone variants alters the functional properties of chromatin. To understand the global dynamics of chromatin structure and function, analysis of Histone variants incorporated into the nucleosome and their covalent modifications is required. Here we report the first global mass spectrometric analysis of Histone H2A and H2B variants derived from Jurkat cells. A combination of mass spectrometric techniques, HPLC separations, and enzymatic digestions using endoproteinase Glu-C, endoproteinase Arg-C, and trypsin were used to identify Histone H2A and H2B subtypes and their modifications. We identified nine Histone H2A and 11 Histone H2B subtypes, among them proteins that only had been postulated at the gene level. The two main H2A variants, H2AO and H2AC, as well as H2AL were either acetylated at Lys-5 or phosphorylated at Ser-1. For the replacement Histone H2AZ, acetylation at Lys-4 and Lys-7 was found. The main Histone H2B variant, H2BA, was acetylated at Lys-12, -15, and -20. The analysis of core Histone subtypes with their modifications provides a first step toward an understanding of the functional significance of the diversity of Histone structures.