Functional analyses of the polycomb-group genes in sea lamprey embryos undergoing programmed DNA loss.
Functional analyses of the polycomb-group genes in sea lamprey embryos undergoing programmed DNA loss.
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对经历程序性 DNA 丢失的海七鳃鳗胚胎中多梳群基因的功能分析。
DOI：
10.1002/jez.b.23225
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Smith,JeramiahJ
中科院分区：
文献类型：
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作者：
Saraceno,Cody;Timoshevskiy,VladimirA;Smith,JeramiahJ
在早期发育过程中，七鳃鳗胚胎经历了一种被称为程序性基因组重排(PGR)的过程，从体祖细胞中程序性地消除DNA。消除的DNA最终会浓缩成微核，然后在物理上降解并永久从细胞中消失。以往的研究表明，在PGR过程中消除的许多基因都有哺乳动物同源基因，这些基因与胚胎干细胞中的多梳抑制复合体(PRC)结合。为了测试PRC组件是否在生殖系特异序列的忠实消除中发挥作用，我们使用CRISPR/Cas9和LightSheet显微镜相结合的方法来研究基因敲除对早期发育和DNA消除阶段进展的影响。对PRC2核心亚基EZH、SUZ12和EED基因敲除胚胎的分析表明，这三个基因的破坏都会导致微核数量增加，改变微核在胚胎中的分布，并增加突变胚胎的微核体积。虽然DNA消除的上游事件不会受到PrC2组分丢失的强烈影响，但本研究表明，PrC2在与微核凝聚和降解有关的消除的后期阶段发挥作用。这些发现还表明，在DNA消除过程中，其他基因/表观遗传途径可能并行工作，以调节染色质结构、可及性和生殖系特有DNA的最终丢失。
During early development, sea lamprey embryos undergo programmatic elimination of DNA from somatic progenitor cells in a process termed programmed genome rearrangement (PGR). Eliminated DNA eventually becomes condensed into micronuclei, which are then physically degraded and permanently lost from the cell. Previous studies indicated that many of the genes eliminated during PGR have mammalian homologs that are bound by polycomb repressive complex (PRC) in embryonic stem cells. To test whether PRC components play a role in the faithful elimination of germline‐specific sequences, we used a combination of CRISPR/Cas9 and lightsheet microscopy to investigate the impact of gene knockouts on early development and the progression through stages of DNA elimination. Analysis of knockout embryos for the core PRC2 subunits EZH, SUZ12, and EED show that disruption of all three genes results in an increase in micronucleus number, altered distribution of micronuclei within embryos, and an increase in micronucleus volume in mutant embryos. While the upstream events of DNA elimination are not strongly impacted by loss of PRC2 components, this study suggests that PRC2 plays a role in the later stages of elimination related to micronucleus condensation and degradation. These findings also suggest that other genes/epigenetic pathways may work in parallel during DNA elimination to mediate chromatin structure, accessibility, and the ultimate loss of germline‐specific DNA.