Nuclear-cytoplasmic interactions in mammalian embryos

哺乳动物胚胎中的核-细胞质相互作用

• 批准号: RGPIN-2015-06228
• 负责人: Smith, Lawrence
• 金额: $ 2.04万
• 依托单位: Université de Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=665473
• 关键词: Nuclear; cytoplasmic; interactions; mammalian; embryos

Reproductive success is the single most important measurement of progress of animal breeding programs. However, reproductive success in high-performing domestic animals is significantly compromised by elevated embryonic mortality during gestation and postnatal morbidity. This is particularly true in gestations resulting from assisted reproductive techniques (ART) such as the in vitro production of embryos and somatic cell nuclear transfer (SCNT). In these animals, little is known of the etiology of the developmental abnormalities associated with ART, which include the Large Offspring Syndrome, indicating that further research is needed to elucidate the biological mechanisms and to improve the efficiency of ART for animal breeding practices. Therefore, my research interests are aimed at exploring the epigenetic phenomena of cell reprogramming with emphasis on those involved in the pre- and postnatal developmental losses caused by ART. Chromatin remodeling is a key feature of the successful reprogramming by SCNT and in derivation of induced pluripotent stem (iPS) cells. Genomic imprinting is an epigenetic phenomenon that enables the monoallelic expression of a group of developmentally important genes in a parent-of-origin fashion through the allele-specific methylation of differentially methylated regions. Since most imprinted genes have been studied in laboratory animals, preliminary characterization of these imprinted control regions is required to enable studies in the large animals. Therefore, my principal objective is to improve our understanding of the epigenetic interactions between nuclei and cytoplasm during chromatin remodelling in mammals, particularly in domestic species. Our hypothesis is that the reprogramming of somatic cell nuclei involves epigenetic modification directed by cytoplasmic components that allow normal spatial and temporal patterns of gene expression during early development. The specific objectives are to (1) characterize the epigenetic anomalies associated with success and failure during development of embryos derived by ART, particularly in vitro fertilization and consequent in vitro culture, SCNT and pluripotent stem cells, and (2) investigate the molecular mechanisms controlling the erasure and establishment of epigenetic marks in the differentially methylated regions of imprinted genes and their parental-specific and overall expression patterns. Together, the findings from this research program will have significant impact on our understanding of the epigenetic mechanisms of chromatin reprogramming during early development in large domestic animals, providing a better understanding of how the oocyte is able to effectively reprogram somatic nuclei. In practice, these studies will enable the creation of novel and improved tools that assure a safe and efficient use of ART in farm animal breeding practices.**

繁殖成功是衡量动物育种计划进展的唯一最重要的衡量标准。然而，高性能家畜的繁殖成功受到妊娠期胚胎死亡率和出生后发病率的显著影响。这在辅助生殖技术(ART)导致的妊娠中尤其如此，例如体外胚胎生产和体细胞核移植(SCNT)。在这些动物中，与ART相关的发育异常的病因知之甚少，包括大后代综合症，这表明需要进一步的研究来阐明生物学机制，并提高ART在动物育种实践中的效率。因此，我的研究兴趣旨在探索细胞重新编程的表观遗传学现象，重点是那些参与ART导致的出生前和出生后发育损失的因素。染色质重塑是SCNT成功重编程和诱导多能干细胞(IPS)分化的关键特征。基因组印迹是一种表观遗传现象，它通过差异甲基化区域的等位基因特异性甲基化，以亲本方式使一组发育重要基因的单等位基因表达。由于大多数印迹基因已经在实验室动物中进行了研究，因此需要对这些印迹控制区进行初步表征，以便能够在大型动物中进行研究。因此，我的主要目标是提高我们对哺乳动物，特别是家养物种染色质重塑过程中细胞核和细胞质之间的表观遗传相互作用的理解。我们的假设是，体细胞核的重新编程涉及由细胞质成分指导的表观遗传修饰，从而允许在早期发育过程中正常的基因表达的时空模式。其具体目标是(1)描述在ART胚胎发育过程中与成功和失败相关的表观遗传学异常，特别是体外受精和随后的体外培养、SCNT和多能干细胞，以及(2)研究控制印记基因差异甲基化区域表观遗传标记的擦除和建立的分子机制及其父母特有的和整体的表达模式。综上所述，该研究项目的发现将对我们理解大型家畜早期发育过程中染色质重编程的表观遗传机制产生重大影响，为更好地理解卵母细胞如何能够有效地对体细胞核进行重编程提供依据。在实践中，这些研究将能够创造新的和改进的工具，确保在农场动物饲养实践中安全和有效地使用ART。