{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\n Histone H2AC13 is one of the replication‐dependent core histone variants that, as an integral component of the nucleosome, contributes not only to chromatin compaction but also to the regulation of gene expression, cellular differentiation, and DNA repair. In several studies, H2A isoforms interacting with key repair proteins, such as MGMT, have been shown to enhance DNA repair activity and thereby promote genomic stability."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": " In the context of carcinogenesis, altered expression of H2A variants is frequently observed; increased levels of H2A isoforms (for example, those akin to H2AC13) correlate with dedifferentiation and the maintenance of an undifferentiated state in hepatocytes, suggesting a role in tumor progression and cell fate determination."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": " Furthermore, detailed mutagenesis and functional studies have demonstrated that while the N-terminal tail acetylation of major H2A variants may be nonessential for cell viability, it contributes to the establishment of a critical charge patch that governs nucleosome stability and interactions with chromatin remodelers."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": " Beyond its canonical role in organizing DNA, H2A isoforms have been implicated in nonchromatin functions; for instance, several reports indicate that the C-terminal regions of these proteins can bind bacterial lipopolysaccharide with high specificity and affinity—this interaction in turn can modulate immune cell activation and inflammatory signaling."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "5"}]}, {"type": "t", "text": " In addition, environmental stresses such as exposure to polycyclic aromatic hydrocarbons result in altered abundance of H2A variants, highlighting their involvement in cellular stress responses."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "6"}]}, {"type": "t", "text": " Finally, the observation that transcripts encoding these histone variants remain stably expressed during key developmental transitions further underscores their function as dynamic regulators of chromatin architecture and gene expression programs."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "7"}]}, {"type": "t", "text": "\n "}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Suryakant K Niture, Catalin E Doneanu, Chinavenmeni S Velu, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Proteomic analysis of human O6-methylguanine-DNA methyltransferase by affinity chromatography and tandem mass spectrometry."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Biochem Biophys Res Commun (2005)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.bbrc.2005.09.177"}], "href": "https://doi.org/10.1016/j.bbrc.2005.09.177"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "16226712"}], "href": "https://pubmed.ncbi.nlm.nih.gov/16226712"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Monica Tyagi, Bharat Khade, Shafqat A Khan, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Expression of histone variant, H2A.1 is associated with the undifferentiated state of hepatocyte."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Exp Biol Med (Maywood) (2014)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1177/1535370214531869"}], "href": "https://doi.org/10.1177/1535370214531869"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "24764240"}], "href": "https://pubmed.ncbi.nlm.nih.gov/24764240"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Monica Tyagi, Divya Reddy, Sanjay Gupta "}, {"type": "b", "children": [{"type": "t", "text": "Genomic characterization and dynamic methylation of promoter facilitates transcriptional regulation of H2A variants, H2A.1 and H2A.2 in various pathophysiological states of hepatocyte."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Int J Biochem Cell Biol (2017)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.biocel.2017.01.019"}], "href": "https://doi.org/10.1016/j.biocel.2017.01.019"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "28163185"}], "href": "https://pubmed.ncbi.nlm.nih.gov/28163185"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Qinghu Ren, Martin A Gorovsky "}, {"type": "b", "children": [{"type": "t", "text": "The nonessential H2A N-terminal tail can function as an essential charge patch on the H2A.Z variant N-terminal tail."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Mol Cell Biol (2003)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1128/MCB.23.8.2778-2789.2003"}], "href": "https://doi.org/10.1128/MCB.23.8.2778-2789.2003"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "12665578"}], "href": "https://pubmed.ncbi.nlm.nih.gov/12665578"}]}, {"type": "r", "ref": 5, "children": [{"type": "t", "text": "Luis A Augusto, Paulette Decottignies, Monique Synguelakis, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Histones: a novel class of lipopolysaccharide-binding molecules."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Biochemistry (2003)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1021/bi0268394"}], "href": "https://doi.org/10.1021/bi0268394"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "12667084"}], "href": "https://pubmed.ncbi.nlm.nih.gov/12667084"}]}, {"type": "r", "ref": 6, "children": [{"type": "t", "text": "Louisa Ada Hooven, William M Baird "}, {"type": "b", "children": [{"type": "t", "text": "Proteomic analysis of MCF-7 cells treated with benzo[a]pyrene, dibenzo[a,l]pyrene, coal tar extract, and diesel exhaust extract."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Toxicology (2008)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.tox.2008.03.019"}], "href": "https://doi.org/10.1016/j.tox.2008.03.019"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "18495319"}], "href": "https://pubmed.ncbi.nlm.nih.gov/18495319"}]}, {"type": "r", "ref": 7, "children": [{"type": "t", "text": "Christian Vigneault, Isabelle Gilbert, Marc-André Sirard, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Using the histone H2a transcript as an endogenous standard to study relative transcript abundance during bovine early development."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Mol Reprod Dev (2007)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1002/mrd.20665"}], "href": "https://doi.org/10.1002/mrd.20665"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "17133602"}], "href": "https://pubmed.ncbi.nlm.nih.gov/17133602"}]}]}]}