Section of Developmental Genomics, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, United States.
Department of Biology, Johns Hopkins University, Baltimore, United States.
Elife. 2024 Sep 18;13:RP94631. doi: 10.7554/eLife.94631.
Differentiation of female germline stem cells into a mature oocyte includes the expression of RNAs and proteins that drive early embryonic development in . We have little insight into what activates the expression of these maternal factors. One candidate is the zinc-finger protein OVO. OVO is required for female germline viability and has been shown to positively regulate its own expression, as well as a downstream target, , by binding to the transcriptional start site (TSS). To find additional OVO targets in the female germline and further elucidate OVO's role in oocyte development, we performed ChIP-seq to determine genome-wide OVO occupancy, as well as RNA-seq comparing hypomorphic and wild type rescue alleles. OVO preferentially binds in close proximity to target TSSs genome-wide, is associated with open chromatin, transcriptionally active histone marks, and OVO-dependent expression. Motif enrichment analysis on OVO ChIP peaks identified a 5'-TAACNGT-3' OVO DNA binding motif spatially enriched near TSSs. However, the OVO DNA binding motif does not exhibit precise motif spacing relative to the TSS characteristic of RNA polymerase II complex binding core promoter elements. Integrated genomics analysis showed that 525 genes that are bound and increase in expression downstream of OVO are known to be essential maternally expressed genes. These include genes involved in anterior/posterior/germ plasm specification (), egg activation (), translational regulation (, , ), and vitelline membrane formation (, , ). This suggests that OVO is a master transcriptional regulator of oocyte development and is responsible for the expression of structural components of the egg as well as maternally provided RNAs that are required for early embryonic development.
雌性生殖细胞向成熟卵子的分化包括表达 RNA 和蛋白质，这些 RNA 和蛋白质驱动早期胚胎发育。我们对是什么激活了这些母体因子的表达知之甚少。锌指蛋白 OVO 是一个候选者。OVO 对雌性生殖细胞的存活是必需的，并且已经被证明通过结合转录起始位点 (TSS) 来正向调节自身表达及其下游靶标 。为了在雌性生殖细胞中找到额外的 OVO 靶标，并进一步阐明 OVO 在卵母细胞发育中的作用，我们进行了 ChIP-seq 以确定全基因组 OVO 占据，以及 RNA-seq 比较低功能和野生型 rescue 等位基因。OVO 优先在全基因组上靠近靶 TSS 的位置结合，与开放染色质、转录活性组蛋白标记和 OVO 依赖的表达相关。对 OVO ChIP 峰的基序富集分析确定了一个 5'-TAACNGT-3' OVO DNA 结合基序，该基序在 TSS 附近空间富集。然而，与 RNA 聚合酶 II 复合物结合核心启动子元件的 TSS 特征相比，OVO DNA 结合基序没有表现出精确的基序间隔。综合基因组分析表明，在 OVO 下游结合并增加表达的 525 个基因是已知的必需母源表达基因。这些基因包括参与前后/生殖质特化 ()、卵子激活 ()、翻译调控 () 和卵黄膜形成 () 的基因。这表明 OVO 是卵母细胞发育的主要转录调节因子，负责表达卵子的结构成分以及早期胚胎发育所需的母体提供的 RNA。
