Dual RNA 3’-end processing of H2A.X messenger RNA maintains DNA damage repair throughout the cell cycle

• Published in: Nature communications Vol. 12; no. 1; p. 359
• Main Authors: Griesbach, Esther, Schlackow, Margarita, Marzluff, William F., Proudfoot, Nick J.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 13.01.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 13; 13/1; 13/106; 13/109; 13/31; 13/44; 13/89; 45; 45/22; 45/23; 45/41; 45/77; 45/90; 45/91; 631/208/200; 631/337/1427; 631/337/1645; 631/45/500; Cell cycle; Cell Cycle - genetics; Cell Line; Cell lines; Chromatin; Damage; Deoxyribonucleic acid; DNA; DNA - genetics; DNA - metabolism; DNA biosynthesis; DNA Damage; DNA Repair; DNA Replication - genetics; Epigenetics; Eukaryotes; Gene expression; Gene Expression Regulation; Genes; HCT116 Cells; HeLa Cells; Histones; Histones - genetics; Histones - metabolism; Humanities and Social Sciences; Humans; Isoforms; Jurkat Cells; multidisciplinary; Poly A - genetics; Poly A - metabolism; Poly(A); Repair; Replication; Ribonucleic acid; RNA; RNA processing; RNA, Messenger - genetics; RNA, Messenger - metabolism; Science; Science (multidisciplinary); Synthesis
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-20520-6

Phosphorylated H2A.X is a critical chromatin marker of DNA damage repair (DDR) in higher eukaryotes. However, H2A.X gene expression remains relatively uncharacterised. Replication-dependent (RD) histone genes generate poly(A)- mRNA encoding new histones to package DNA during replication. In contrast, replication-independent (RI) histone genes synthesise poly(A)+ mRNA throughout the cell cycle, translated into histone variants that confer specific epigenetic patterns on chromatin. Remarkably H2AFX , encoding H2A.X, is a hybrid histone gene, generating both poly(A)+ and poly(A)- mRNA isoforms. Here we report that the selective removal of either mRNA isoform reveals different effects in different cell types. In some cells, RD H2A.X poly(A)- mRNA generates sufficient histone for deposition onto DDR associated chromatin. In contrast, cells making predominantly poly(A)+ mRNA require this isoform for de novo H2A.X synthesis, required for efficient DDR. This highlights the importance of differential H2A.X mRNA 3’-end processing in the maintenance of effective DDR. H2A.X histone variant gene encodes poly(A)+ and poly(A)- mRNA isoforms which are differentially expressed depending on cell lines. Here the authors show that upon DNA damage, cells expressing more poly(A)+ isoform require this isoform for de novo H2A.X synthesis while cells with more poly(A)- isoform have sufficient H2A.X present in chromatin.