Elucidating the molecular basis of lncRNA evolution for mammalian dosage compensation

阐明哺乳动物剂量补偿的 lncRNA 进化的分子基础

• 批准号: 10471854
• 负责人: Sha Sun
• 金额: $ 31.98万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10471854
• 关键词: Affect; Animals; Binding; CRISPR/Cas technology; Cells; Cessation of life; Chromosomes; Code; Conserved Sequence; Data; Deer Mouse; Defect; Development; Diagnostic; Disease; Distant; Dosage Compensation (Genetics); Dose; Elements; Embryo; Engineering; Evolution; Experimental Models; Failure; Female; Gene Cluster; Gene Expression; Gene Expression Regulation; Gene Silencing; Genes; Genetic Transcription; Genetic Variation; Health; Human; Hybrids; In Vitro; Knock-in; Knowledge; Lead; Length; Light; Link; Malignant Neoplasms; Mammals; Maps; Marsupialia; Measures; Mediating; Methods; Modeling; Molecular; Mus; Nucleotides; Pattern; Peromyscus; Phylogenetic Analysis; Plants; Prevention; Primates; Property; Proteins; RNA; Reporting; Research; Rodent; Role; Sequence Alignment; Sex Chromosomes; Site; Site-Directed Mutagenesis; Structure; System; Transcript; Transgenes; Transgenic Mice; Transgenic Organisms; Untranslated RNA; Variant; X Chromosome; X Inactivation; XY females; Y Chromosome; autosome; blastomere structure; developmental disease; embryonic stem cell; epigenetic regulation; fly; gene product; genetic evolution; genetic sex determination; human disease; in vivo; insight; male; mouse genome; sex; stem

ABSTRACT Genetic sex determination and sex chromosomes have evolved in both animals and plants. In mammals, males are XY and females are XX. Degeneration of the Y chromosome and the difference in the number of X- chromosome would lead to dose imbalance of X-linked gene products between male and female cells. To resolve this problem, various dosage compensation mechanisms have evolved in heterogametic species. In mammals, one of the two X chromosomes is transcriptionally silenced in females during X-inactivation. While X-inactivation has been extensively studied as a paradigm for epigenetic regulation of sex chromosomes, it is largely controlled by long noncoding RNAs (lncRNAs) that remain elusive for their role in the evolution of dosage compensation mechanisms. In general, human lncRNAs impact early development and affect human disease. However, whether lncRNAs represent “byproducts” of transcription or essential biomolecules in gene regulation, e.g. X- inactivation, has been under continuous debate. Experimental models for functional lncRNA and evolution of RNA-mediated mechanisms are scarce. Our research focuses on a cluster of lncRNA genes functional for X-inactivation. This cluster of lncRNA genes have evolved concomitantly on the X chromosome, from ancestral protein-coding genes through pseudogenization and gain of RNA functions, coincidental with the evolution of X-inactivation along the divergence of eutherian and marsupial mammals. Our recent data have demonstrated that, within this gene cluster in the mouse genome, the lncRNA Jpx activates lncRNA Xist and functions as a molecular switch for mouse X-inactivation. We have also reported, by comparing mouse and human homologs, functional conservation of Jpx in X-inactivation despite overall sequence and RNA structural divergence. But questions regarding 1) what sequence variations are determinant of lncRNA function for X-inactivation, 2) are there regulatory features of lncRNA essential for X-inactivation, 3) what drives the function of Xic locus in X- chromosome silencing, are unresolved. These are questions directly related to the evolution of dosage compensation in mammals. In this project, we will (1) determine the regional sequence motifs of Jpx lncRNA that are essential for its function in X-inactivation, (2) determine whether both trans and cis activities of Jpx lncRNA are necessary for its function in X-inactivation, and (3) understand the function of Xic in chromosome silencing and the requirement of its cis and trans activities by integrating the Xic sequence into an autosome. The proposed research is anticipated to uncover insights into the molecular features of lncRNA for function in X-inactivation, which will contribute to our understanding about not only lncRNA evolution, but also dosage compensation evolution in mammals.

抽象的 遗传性别确定和性染色体在动物和植物中都进化。在哺乳动物中， 雄性是XY，女性为xx。 Y染色体的变性和X-数量的差异 染色体会导致男性和雌性细胞之间X连锁基因产物的剂量失衡。解决 这个问题，杂项物种中的各种剂量补偿机制已经发展。在哺乳动物中， 在X灭活过程中，在女性中，两个X染色体之一是在转录中沉默的。而X灭活 已被广泛研究为性别染色体表观遗传调节的范例，它在很大程度上受到控制 通过长期非编码RNA（LNCRNA），它在剂量补偿的演变中仍然难以捉摸 机制。通常，人类lncRNA会影响早期发育并影响人类疾病。然而， LNCRNA是否代表转录的“副产品”，还是基因调节中必需的生物分子，例如X- 失活，一直处于持续的辩论中。功能性lncRNA的实验模型和演变 RNA介导的机制很少。 我们的研究重点是用于X灭活的LNCRNA基因簇。这个lncrna群 基因从祖先蛋白编码基因通过 RNA功能的假基础和增益，与X灭活的演变一致 Eutherian和Marsipial哺乳动物的分歧。我们最近的数据表明，在此基因中 群集在小鼠基因组中，lncRNA JPX激活lncRNA xist，并用作分子开关 鼠标X灭活。我们还报告了通过比较小鼠和人类同源物的功能 JPX在X灭活目的地的总体序列和RNA结构差异中的保存。但是问题 关于1）X灭活的LNCRNA函数确定了哪些序列变化，2） lncRNA的调节特征对于X灭活必不 染色体沉默尚未解决。这些是与剂量演变直接相关的问题 哺乳动物的补偿。在这个项目中，我们将（1）确定JPX lncRNA的区域序列基序 （2）确定JPX lncRNA的反式和顺式活性是否对其在X灭活中的功能至关重要 对于X灭活中的功能是必需的，（3）了解XIC在染色体沉默中的功能 以及通过将XIC序列整合到常染色体中，其顺式和反式活动的要求。提议 预计研究会发现对lncRNA的分子特征的见解，以在X灭活中的功能， 这将有助于我们对lncrna进化的理解，还会有助于剂量补偿 哺乳动物的进化。