Establishment of the meiotic cell cycle program through post-transcriptional regulation by MEIOC and YTHDC2

通过 MEIOC 和 YTHDC2 的转录后调控建立减数分裂细胞周期程序

• 批准号: 10553538
• 负责人: Maria Mikedis
• 金额: $ 6.34万
• 依托单位: WHITEHEAD INSTITUTE FOR BIOMEDICAL RES
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-03-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10553538
• 关键词: Affect; Aneuploidy; Animal Model; Binding; Cell Cycle; Cell Cycle Progression; Cell Cycle Regulation; Characteristics; Chromosome Segregation; Chromosomes; Complex; Congenital Abnormality; Cyclins; DNA biosynthesis; Defect; Development; Diploidy; Event; Exhibits; Failure; Female; Fertility; Genes; Genetic Recombination; Genetic Transcription; Germ Cells; Germ Lines; Goals; Haploidy; Health; Hela Cells; Human; Infertility; Knowledge; Lead; Length; Life; Malignant Neoplasms; Mammals; Mediating; Meiosis; Meiotic Prophase I; Messenger RNA; Metaphase; Mitosis; Mitotic; Mitotic Prophase; Modification; Molecular; Molecular Abnormality; Mus; Organism; Outcome; Post-Transcriptional Regulation; Pregnancy; Preventive treatment; Prophase; Proteins; Publishing; RNA; Regulation; Research; Sampling; Series; Spontaneous abortion; Testing; Transcript; Translational Repression; Translations; Ubiquitination; Up-Regulation; Work; base; cancer therapy; cell transformation; chromosome missegregation; egg; insight; male; predictive modeling; premature; prevent; programs; protein expression; sperm cell

PROJECT SUMMARY/ABSTRACT Diploid germ cells are transformed into haploid gametes via the reductive division of meiosis. After meiotic DNA synthesis, germ cells enter meiotic prophase I, which distinguishes itself from mitotic prophase by two major characteristics. First, meiotic prophase I is dramatically longer than mitotic prophase. Second, meiotic prophase I involves an intricate series of chromosomal events that contribute to the establishment of the haploid state. The extended length of prophase I is critical for the completion of these chromosomal events, as premature exit from prophase I causes recombination defects and chromosome mis-segregation. In mammals, meiotic prophase I is prolonged by Meioc and Ythdc2. In the absence of either gene in both males and females, meiotic germ cells fail to complete meiotic prophase I and prematurely enter an abnormal metaphase before ultimately apoptosing. Several preliminary observations suggest that MEIOC and YTHDC2 function as a complex to post-transcriptionally regulate cell cycle factors within meiotic germ cells. MEIOC and YTHDC2 are first expressed in the germ line at meiotic initiation, and they interact with one another as well as with an overlapping set of transcripts, including key cell cycle regulators. These targets are enriched for the RNA modification N6-methyladenosine (m6A), which is preferentially recognized by YTHDC2’s YTH domain and which is used to target and post-transcriptionally regulate RNA. In the absence of Meioc, MEIOC and YTHDC2’s targets exhibit reduced stability. Changes in transcript stability are oftentimes accompanied by changes in translation, and in HeLa cells, YTHDC2 enhances translational efficiency while decreasing mRNA abundance. However, it remains unknown whether MEIOC and YTHDC2 affect translation in meiotic germ cells. This proposal will test the hypothesis that MEIOC and YTHDC2 function as a complex to recognize and translationally regulate m6A-modified mRNA in order to establish a meiosis-specific cell cycle program. This hypothesis will be tested via three specific aims. The first aim will assess MEIOC’s ability to affect YTHDC2’s interactions with RNA, particularly cell cycle-related transcripts, by identifying the transcripts that YTHDC2 binds to in the presence and absence of Meioc. In addition, whether m6A contributes to MEIOC and YTHDC2’s ability to interact with RNA will also be assessed. The second aim will identify the translational changes that occur as germ cells transition from mitosis to meiosis, as well as between wild-type and Meioc-null samples. In particular, this aim will determine whether cell cycle factors are translationally repressed at the onset of meiosis and by the upregulation of Meioc. The third aim will determine whether MEIOC and YTHDC2 are continuously required during meiotic prophase I to prevent precocious cell cycle progression. In addition, the third aim will identify the mechanistic regulation behind this putative requirement. These fundamental studies on MEIOC and YTHDC2’s regulation of the length of meiotic prophase I will provide key insights into the establishment and regulation of the meiotic cell cycle program, with broader implications for fertility, development, and cancer.

项目概要/摘要 二倍体生殖细胞通过减数分裂的还原分裂转化为单倍体配子。减数分裂后 DNA合成，生殖细胞进入减数分裂前期I，它与有丝分裂前期有两个区别 主要特点。首先，减数分裂前期 I 比有丝分裂前期长得多。二、减数分裂 前期 I 涉及一系列复杂的染色体事件，这些事件有助于建立 单倍体状态。前期 I 的延长长度对于完成这些染色体事件至关重要，因为 提前退出前期 I 会导致重组缺陷和染色体错误分离。在哺乳动物中， Meioc 和 Ythdc2 延长了减数分裂前期 I。如果雄性和雌性体内均不存在任一基因， 女性，减数分裂生殖细胞未能完成减数分裂前期 I 并过早进入异常中期 在最终凋亡之前。一些初步观察表明 MEIOC 和 YTHDC2 的功能是 减数分裂生殖细胞内转录后调节细胞周期因子的复杂性。 MEIOC 和 YTHDC2 是 在减数分裂起始时首先在种系中表达，并且它们彼此相互作用以及与 重叠的转录本集，包括关键的细胞周期调节因子。这些靶标富含 RNA 修饰 N6-甲基腺苷 (m6A)，优先被 YTHDC2 的 YTH 结构域识别， 它用于靶向和转录后调节RNA。在没有 Meioc 的情况下，MEIOC 和 YTHDC2 的目标表现出稳定性降低。转录稳定性的变化通常伴随着 翻译的变化，在 HeLa 细胞中，YTHDC2 提高翻译效率，同时减少 mRNA 丰富。然而，MEIOC 和 YTHDC2 是否影响减数分裂胚中的翻译仍不清楚 细胞。该提案将测试 MEIOC 和 YTHDC2 作为复合体的假设，以识别和识别 翻译调节 m6A 修饰的 mRNA，以建立减数分裂特异性的细胞周期程序。这 假设将通过三个具体目标进行检验。第一个目标将评估 MEIOC 影响 YTHDC2 的能力 通过识别 YTHDC2 与 RNA 的相互作用，特别是与细胞周期相关的转录物 在存在或不存在 Meioc 的情况下结合。另外，m6A是否对MEIOC和YTHDC2的贡献 与 RNA 相互作用的能力也将被评估。第二个目标将确定转化变化 当生殖细胞从有丝分裂过渡到减数分裂时，以及在野生型和 Meioc-null 样本之间发生。在 特别是，这个目标将确定细胞周期因子在减数分裂开始时是否受到翻译抑制 以及 Meioc 的上调。第三个目标将决定 MEIOC 和 YTHDC2 是否持续 减数分裂前期 I 所需的，以防止细胞周期过早进展。此外，第三个目标将 确定这一假定要求背后的机械调节。这些关于 MEIOC 和 YTHDC2 对减数分裂前期 I 长度的调节将为减数分裂前期 I 的建立和 减数分裂细胞周期程序的调节，对生育、发育和癌症具有更广泛的影响。