A Testis-Specific Chaperone and the Chromatin Remodeler ISWI Mediate Repackaging of the Paternal Genome
A Testis-Specific Chaperone and the Chromatin Remodeler ISWI Mediate Repackaging of the Paternal Genome
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DOI：
10.1016/j.celrep.2015.10.010
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发表时间：
2015-11-17
期刊：
影响因子：
8.8
通讯作者：
Verrijzer, C. Peter
中科院分区：
文献类型：
--
作者：
Doyen, Cecile M.;Chalkley, Gillian E.;Verrijzer, C. Peter
在精子发生过程中，父亲的基因组被重新包装成一个高度紧凑的非核小体染色质结构。生物信息学分析表明，果蝇精子染色质蛋白具有一个与高迁移率族(HMG)盒相关的基序，我们称之为错配转录本(MST)-HMG盒。MST77F是一种MST-HMG-box蛋白，是精子染色质的重要组成部分。MST77F在父本基因组上的沉积需要tNAP的伴侣功能，tNAP是一种睾丸特异的NAP蛋白。反过来，MST77F使MST35BA和MST35Bb稳定地整合到精子染色质中。在MST-HMG-box蛋白沉积之后，依赖于ATP的染色质重构体ISWI介导了精子染色质的适当组织。相反，在受精时，母体ISWI以父亲的基因组为目标，并将其重新包装成去浓缩的核小体染色质。在ISWI突变胚胎中，这一转变失败后会出现有丝分裂缺陷、非整倍体和单倍体胚胎分裂。因此，ISWI能够在两种根本不同形式的染色质之间进行双向转换。
During spermatogenesis, the paternal genome is repackaged into a non-nucleosomal, highly compacted chromatin structure. Bioinformatic analysis revealed that Drosophila sperm chromatin proteins are characterized by a motif related to the high-mobility group (HMG) box, which we termed malespecific transcript (MST)-HMG box. MST77F is a MST-HMG-box protein that forms an essential component of sperm chromatin. The deposition of MST77F onto the paternal genome requires the chaperone function of tNAP, a testis-specific NAP protein. MST77F, in turn, enables the stable incorporation of MST35Ba and MST35Bb into sperm chromatin. Following MST-HMG-box protein deposition, the ATP-dependent chromatin remodeler ISWI mediates the appropriate organization of sperm chromatin. Conversely, at fertilization, maternal ISWI targets the paternal genome and drives its repackaging into de-condensed nucleosomal chromatin. Failure of this transition in ISWI mutant embryos is followed by mitotic defects, aneuploidy, and haploid embryonic divisions. Thus, ISWI enables bi-directional transitions between two fundamentally different forms of chromatin.