Association of Sly with sex-linked gene amplification during mouse evolution: a side effect of genomic conflict in spermatids?
Association of Sly with sex-linked gene amplification during mouse evolution: a side effect of genomic conflict in spermatids?
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DOI：
10.1093/hmg/ddr204
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发表时间：
2011-08-01
影响因子：
3.5
通讯作者：
Affara, Nabeel A.
中科院分区：
文献类型：
--
作者：
Ellis, Peter J. I.;Bacon, Joanne;Affara, Nabeel A.
与其他哺乳动物性染色体一样，小鼠性染色体富含具有男性特异性功能的基因，例如睾丸基因。然而，在小鼠中，含有精子细胞表达基因的扩增序列出现了前所未有的扩展。我们通过对小鼠性染色体上基因扩增的系统发育分析表明，多个性连锁精子细胞表达基因家族在小家鼠亚种和来自古北界小鼠物种的另外两个物种中高度扩增。在其他细胞类型中表达的扩增 X 连锁基因表现出不同的进化轨迹，没有在精子细胞表达的基因中看到的独特的同时扩增。古北区基因扩增与 Sly 的出现同时发生，Sly 是减数分裂后性染色质 (PMSC) 的 Yq 连锁调节因子，其作用是抑制精子细胞中性染色体的转录。尽管基因扩增，但对转录本丰度的影响相对较小，这表明相关基因被扩增是为了克服 Sly 介导的转录抑制并维持精子细胞中稳定的表达水平。结合已知的 Yq/Sly 缺陷对性别比的影响，我们的结果表明 Sly 参与了与一个或多个 X 连锁性别比扭曲基因的基因组冲突。小鼠谱系中新型 PMSC 调节因子 Sly 的最新进化对于使用小鼠模型系统研究精子细胞性染色体动力学具有重要意义。
In common with other mammalian sex chromosomes, the mouse sex chromosomes are enriched for genes with male-specific function such as testis genes. However, in mouse there has been an unprecedented expansion of ampliconic sequence containing spermatid-expressed genes. We show via a phylogenetic analysis of gene amplification on the mouse sex chromosomes that multiple families of sex-linked spermatid-expressed genes are highly amplified in Mus musculus subspecies and in two further species from the Palaearctic clade of mouse species. Ampliconic X-linked genes expressed in other cell types showed a different evolutionary trajectory, without the distinctive simultaneous amplification seen in spermatid-expressed genes. The Palaearctic gene amplification occurred concurrently with the appearance of Sly, a Yq-linked regulator of post-meiotic sex chromatin (PMSC) which acts to repress sex chromosome transcription in spermatids. Despite the gene amplification, there was comparatively little effect on transcript abundance, suggesting that the genes in question became amplified in order to overcome Sly-mediated transcriptional repression and maintain steady expression levels in spermatids. Together with the known sex-ratio effects of Yq/Sly deficiency, our results suggest that Sly is involved in a genomic conflict with one or more X-linked sex-ratio distorter genes. The recent evolution of the novel PMSC regulator Sly in mouse lineages has significant implications for the use of mouse-model systems in investigating sex chromosome dynamics in spermatids.