The role of the endogenous retroviral family, IAP, in placentation.

内源性逆转录病毒家族 IAP 在胎盘形成中的作用。

• 批准号: 10709650
• 负责人: Julie C Baker
• 金额: $ 25.3万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-22 至 2027-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10709650
• 关键词: ATAC-seq; Acceleration; Binding; Binding Proteins; Biology; Cell membrane; Cell physiology; Cell secretion; Cells; Clustered Regularly Interspaced Short Palindromic Repeats; Communication; Data; Decidua; Decidual Cell; Defect; Elements; Embryo; Embryology; Endogenous Retroviruses; Evolution; Family; Frequencies; Gene Expression Regulation; Generations; Genome; Genomics; Goals; Human; Immunity; Investigation; Knock-out; Length; Location; Maternal Behavior; Maternal-Fetal Exchange; Mediating; Mothers; Mus; Mutagens; Mutation; Pattern; Placenta; Placentation; Pregnancy; Protein Family; Proteins; RNA; Regulation; Regulator Genes; Regulatory Element; Reporter; Research; Retrotransposition; Role; Signal Transduction; Somatic Mutation; Source; Testing; Tissues; Transcript; Transgenes; Viral; Viral Physiology; Viral Proteins; bisulfite sequencing; blastocyst; cell growth regulation; extracellular; extracellular vesicles; fetal; gag Gene Products; genetic approach; imprint; in vivo; insight; knock-down; myometrium; particle; protein function; small hairpin RNA; trophoblast stem cell; wound healing

ABSTRACT Endogenous retroviruses (ERVs) constitute 10% of all genomes, yet they remain the wild west of biology, even though they function within the host cell in a myriad of critical ways, including as regulatory elements, as extracellular messengers, as sources of viral-like particles (VLPs), and, importantly, as somatic mutagens. Our overreaching goal is to understand how the ERV family, IAP (Intracisternal type A Protein), functions at the mouse maternal-fetal interface. Thousands of genomic IAP instances exist that consist of gag, pro, pol sequences flanked by LTRs. These instances have lost the ancestral envelope (env) sequence and form naked VLPs that remain inside the cell and can transpose. Today, only a single copy, IAPE-D1, remains with a conserved envelope (env) sequence that mediates extracellular release of its VLPs. This strong evolutionary conservation of the env in IAPE-D1 suggests that it serves an important extracellular function. Thus, IAPs function in two distinct cellular domains: one as an extracellular messenger, and the other as an intracellular source of regulation and mutation. The rigor of prior research strongly supports this hypothesis. More than 50 years ago VLPs were described in placentas of all species, including mouse and human. The source of the mouse VLPs is likely IAP as we find that it is the only ERV family expressed during placentation. Our data suggests that these VLPs are functional as, when we knock down IAP using shRNA in trophoblast stem cells (TSCs) or in mouse embryos, we observe defects in differentiation and placentation. Further, we find that IAP binds specific RNAs in TSCs, including those that mediate differentiation and imprinting, suggesting that IAP VLPs contain cargo. Importantly, we find that IAP protein is expressed in maternal tissues in the absence of transcript, suggesting that it was transported from the neighboring placental cells. Based on our own preliminary results and more than 50 years of prior research on IAP, we hypothesize that 1) the only extracellular IAP, IAPE-D1, is forming VLPs in the mouse placenta that transport specific RNAs into the maternal decidua and 2) the intracellular IAPs serve multiple functions including the generation of naked VLPs that are mutagenic and as sequences that serve as critical regulatory elements within the placenta genome. While human placentas do not have IAP, they do have HERVK, which forms VLPs that are likely to serve similar functions especially given that the placenta is a hotspot for convergent evolution. Overall, this proposal will deliver the function and mechanism of a major fraction of the unexplored genome during pregnancy.

抽象的 内源性逆转录病毒（ERV）占所有基因组的10％，但它们仍然是 生物学，即使它们以多种关键方式在宿主细胞中发挥作用，包括作为调节 元素，作为细胞外信使，作为病毒样颗粒（VLP）的来源，重要的是， 诱变剂。我们的超越目标是了解ERV家族IAP（肠内a型蛋白质）如何 在小鼠母体界面处的功能。存在成千上万的基因组IAP实例，包括堵嘴， pro，pol序列是LTRS的两侧。这些实例失去了祖先的信封（ENV）序列， 形成保留在细胞内部并可以转置的裸体VLP。今天，只有一个副本，即iApe-d1， 带有介导其VLP的细胞外释放的保守包膜（ENV）序列。这很强大 IAPE-D1中ENV的进化保护表明它具有重要的细胞外功能。 因此，IAP在两个不同的细胞结构域中起作用：一个作为细胞外信使，另一个是一个 细胞内调节和突变的来源。 先前研究的严格性强烈支持这一假设。 50多年前的VLP是 在所有物种的胎盘中描述，包括小鼠和人类。鼠标VLP的来源可能是IAP 正如我们发现它是胎盘期间唯一表达的ERV家族。我们的数据表明这些VLP是 当我们使用shRNA在滋养细胞干细胞（TSC）或小鼠胚胎中使用shRNA击倒IAP时，功能为AS时， 我们观察到分化和胎盘的缺陷。此外，我们发现IAP在TSC中结合了特定的RNA， 包括介导分化和烙印的人，表明IAP VLP包含货物。 重要的是，我们发现在没有转录本的情况下，IAP蛋白在母体组织中表达，表明 它是从相邻胎盘细胞中运输的。基于我们自己的初步结果和更多 超过50年的IAP研究，我们假设1）唯一的细胞外IAP IAPE-D1正在形成 小鼠胎盘中的VLP将特异性RNA传输到母体Decidua和2）细胞内 IAP具有多种功能，包括产生诱变的裸体VLP和序列 作为胎盘基因组中的关键调节元件。虽然人胎盘没有IAP，但 他们确实有HERVK，形成了可能具有相似功能的VLP，特别是考虑到 胎盘是用于收敛进化的热点。总体而言，该建议将提供功能和机制 怀孕期间未开发的基因组的主要部分。