Probing the Function of Metazoan Histones with a Systematic Library of H3 and H4 Mutants

Abstract

Highlights d Generation of histone-deletion lines in Drosophila by CRISPR/Cas9 d Histone gene dosage affects oogenesis and spermatogenesis in Drosophila d Hierarchically assembled 40 histone mutants provide a platform for PTM studies d A mosaic system allows functional studies of essential histone mutations

The regulatory genome of the malaria vector Anopheles gambiae: integrating chromatin accessibility and gene expression

“…Certain hPTMs are known to play crucial roles in the remodeling of chromatin structure and transcriptional regulation, with a priori well-established activating (H3K9ac, H3K27ac and H3K4me3) or repressor (H3K9me3) functions ( 77 , 78 ). Activating hPTMs are expected to be enriched at mononucleosomes flanking active and accessible regulatory regions, like TSSs, whereas repressor histone marks are associated with non-accessible and nucleosome-occupied heterochromatin.…”

Histone Variant H3.3 Mutations in Defining the Chromatin Function in Mammals

“…In this regard, the fruit fly represents an exception among metazoans, because all canonical histone genes are organized in tandem repeats located at a single chromosomal locus [ 59 ]. Various genetic tools, such as plasmid and bacterial artificial chromosome (BAC)-based transgenes, and more recently clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9, have been used to replace the wild-type genes with mutated versions [ 59 , 60 , 61 , 62 , 63 ]. This landmark study reported that a lysine-to-arginine substitution at the H3K27 residue (H3K27R) could phenocopy homeotic defects observed in polycomb repressive complex 2 (PRC2) mutants, suggesting a direct role of PRC2-mediated H3K27me3 in this process [ 63 ]).…”

“…Furthermore, a recent systemic study testing alanine substitution of many modifiable histone residues expanded the pool of histone mutants related to Drosophila viability (e.g., H3K4; H3K9; H3K14; H3K27; H3K36). Among the mutants that survived in the early developmental stages, many show reduced fertility (e.g., H3T3A; H3K56A), susceptibility to DNA damage (e.g., H3K56A), and defects in gene silencing (e.g., H3K9A; H3K23A) [ 61 ]. Therefore, it is likely that, with the increasing complexity of multicellular organisms, histone residues have acquired new roles in DNA-related processes.…”

“…While further studies will be necessary in order to investigate the extent of such mechanisms, we speculate that, even if it were possible, a complete loss of a certain H3 histone residue and its associated modifications may cause phenotypes too severe to allow the characterization of the contribution of histone residues in mammals. Studies conducted in Drosophila showed that loss-of-function mutations of residues of the H3 N-terminal tail, such as K4, K9, K27 and K36, among others, are lethal at different developmental stages [ 61 ]. Therefore, the retained modifications on the canonical H3 histones do not necessarily represent a disadvantage.…”

Synthetic biology in China: Review and prospects

“…Church特别提到天津团队用基 因编辑工具CRISPR/Cas9来修复合成基因组中的错 误 [179] . [185] 和目标代谢物优化生产的酵母合成染色 体重排正交系统 [186] , 并与上海理工大学高冠军团队提 出了用于改变组蛋白基因在黑腹果蝇原始基因组环境 中的数量和序列CRISPR/Cas9和attP/attB双整合系 统 [187] ; 北京化工大学刘子鹤团队 [188] 报道了用于酿酒…”