The mRNA "epitranscriptome": delineating its role in regulating gene expression in mammalian oocytes and the impact of assisted reproductive technolog

mRNA“表观转录组”：描述其在调节哺乳动物卵母细胞基因表达中的作用以及辅助生殖技术的影响

• 批准号: 2291570
• 金额: --
• 依托单位: University of Edinburgh
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2291570
• 关键词: mRNA; epitranscriptome; delineating; its; role

Infertility affects roughly 1 in 6 couples worldwide, with 3 million babies having being born using assisted reproduction technologies (ART) by 2018. However, success rates lie at only 20-35% per cycle, with NHS resource restrictions meaning that the number of cycles per couple is limited. After age 42, success rates for women plummet to 4%, which is problematic as women are increasingly delaying childbirth. Moreover there is also an increased treatment need from cancer survivors as chemotherapeutics can negatively affect fertility. Thus to be able to predict individual fertility and to improve treatments for those with compromised fertility, there is a need to understand the basic mechanisms that underpin the survival and development of germ cells.In roughly 50% of cases the partner with compromised fertility is female. Women are born with a finite number of oocytes, with menopause occurring when these become depleted. Oocytes are maintained in "follicles" in close association with support cells known as granulosa cells. Follicles from this pool become activated and grow prior to ovulation. The survival, growth and development of follicles relies on intricate control of gene expression.The advent of new sequencing technologies now offers the possibility of understanding the complexity of gene expression that underlies the growth, maturation, fertilisation and development of early embryos, in detail previously unimaginable. Such studies have revealed differences in the transcriptome (or complement of mRNAs) between in vivo and in vitro matured oocytes. However, post-transcriptional control mechanisms, such as regulated mRNA translation/stability are equally key to maintaining fertility but much less well understood.Importantly, work in other fields particularly from those studying cancer, cell differentiation and the brain has uncovered an exciting new mechanism of regulating mRNA translation/stability, launching a new field known as "epitranscriptomics" in analogy to the field of epigenetics. This advance came from Next Generation Sequencing (NGS) which revealed that modifications (methylations, most frequently m6A) of the nucleotides of mRNAs occur frequently. Whilst DNA methylation and its role in epigenetics is well understood, the function of these modifications in RNA is only just starting to emerge. However they appear to play critical roles on controlling the translation/stability of mRNAs by affecting the binding of RNA-binding proteins.Importantly, the impact of this type of regulation on female fertility in mammals remains to be explored. Recent work has shown it is critical for the oocyte to zygote transition in zebrafish (1) and meiotic progression during mouse spermatogenesis (2), supporting the hypothesis that it will also be important for female fertility in mammals.Thus this project will use cutting-edge NGS applications to map the epitranscriptome of developing oocytes and compare them to those developed in vitro, to understand the impact of ART technologies on gene expression. This will be done in mouse but where appropriate, findings will be translated in humans using unique resources available within Edinburgh.

全球约有六分之一的夫妇患有不孕症，到2018年，将有300万婴儿使用辅助生殖技术(ART)出生。然而，每个周期的成功率只有20%-35%，NHS的资源限制意味着每对夫妇的周期数是有限的。42岁以后，女性的成功率骤降至4%，这是一个问题，因为女性越来越推迟生育。此外，癌症幸存者的治疗需求也在增加，因为化疗可能会对生育产生负面影响。因此，为了能够预测个体生育力并改进对生育力受损的人的治疗，有必要了解支撑生殖细胞生存和发育的基本机制。在大约50%的病例中，生育力受损的伴侣是女性。女性出生时拥有有限数量的卵母细胞，当这些卵母细胞耗尽时，就会发生更年期。卵母细胞被维持在“卵泡”中，与颗粒细胞的支持细胞密切相关。这个池中的卵泡在排卵前被激活并生长。卵泡的存活、生长和发育依赖于对基因表达的复杂控制。新测序技术的出现现在提供了理解基因表达复杂性的可能性，这些基因表达是早期胚胎生长、成熟、受精和发育的基础，以前无法想象。这类研究揭示了体内成熟卵母细胞和体外成熟卵母细胞在转录组(或mRNAs的补体)上的差异。然而，转录后控制机制，如受调控的mRNA翻译/稳定，对维持生育能力同样关键，但远未得到很好的理解。重要的是，在其他领域的工作，特别是来自癌症、细胞分化和大脑的研究，发现了一种令人兴奋的新机制，调节mRNA翻译/稳定，启动了一个新的领域，类似于表观遗传学领域，被称为“表观转录组学”。这一进展来自下一代测序(NGS)，它揭示了mRNAs核苷酸的修饰(甲基化，最常见的是m6A)经常发生。虽然DNA甲基化及其在表观遗传学中的作用已经被很好地理解，但这些修饰在RNA中的功能才刚刚开始显现。然而，它们似乎通过影响RNA结合蛋白的结合而在控制mRNAs的翻译/稳定方面发挥关键作用。重要的是，这种类型的调控对哺乳动物雌性生育的影响仍有待探索。最近的研究表明，斑马鱼的卵子到受精卵的转变(1)和小鼠精子发生过程中的减数分裂进程(2)是至关重要的，这支持了这一假设，即这对哺乳动物的雌性生育能力也是重要的。因此，该项目将使用尖端的NGS应用程序来绘制发育中的卵母细胞的表观转录组图，并将其与体外开发的表型进行比较，以了解ART技术对基因表达的影响。这将在老鼠身上完成，但在适当的情况下，研究结果将使用爱丁堡提供的独特资源在人类身上进行翻译。