有袋動物胚胎發育和X染色體失活單細胞轉錄組圖譜的揭示
作者:
小柯機器人發布時間:2020/8/21 15:43:54
英國弗朗西斯·克裡克研究所James M. A. Turner課題組取得一項新突破。他們揭示了的有袋動物胚胎發育和X染色體失活單細胞轉錄組圖譜。相關論文於2020年8月19日在線發表於國際學術期刊《自然》雜誌上。
研究人員利用單細胞RNA測序對有袋動物灰短尾負鼠(Monodelphis domestica)的胚胎發育和X染色體失活進行了分析。研究人員揭示了表皮細胞、原始內胚層和滋養外胚層的發育軌跡和轉錄特徵,並鑑定了真獸亞綱動物-有袋動物分離之前深度保守的譜系特異標記。RSX包被和X染色體失活在發育早期快速產生。該研究結果支持以下假說:在具有早期X染色體失活的生物中,印跡X染色體失活可阻止雙等位基因X沉默。研究人員確定由活躍X染色體表達的RSX反義轉錄物XSR可能是印跡X染色體失活的調節因子。該研究數據集在進化上提供了對哺乳動物胚胎發育和X劑量補償的新見解。
研究人員表示,胚胎單細胞RNA測序可以在前所未有的解析度水平揭示發育過程中的轉錄情況。迄今為止,關於哺乳動物胚胎單細胞RNA測序的研究主要集中在真哺乳亞綱動物。對哺乳動物之外群體的分析有可能發現高度保守的譜系特徵和多能性因素,並且可以擴展人們對X劑量補償的理解。大約在1.6億年前,後哺乳下綱(有袋類)哺乳動物與真獸亞綱哺乳動物分離。它們具有獨特的發育特徵,包括晚期著床和印跡X染色體失活,這與XIST樣非編碼RNA RSX3的表達有關。
附:英文原文
Title: A single-cell transcriptome atlas of marsupial embryogenesis and X inactivation
Author: Shantha K. Mahadevaiah, Mahesh N. Sangrithi, Takayuki Hirota, James M. A. Turner
Issue&Volume: 2020-08-19
Abstract: Single-cell RNA sequencing of embryos can resolve the transcriptional landscape of development at unprecedented resolution. To date, single-cell RNA-sequencing studies of mammalian embryos have focused exclusively on eutherian species. Analysis of mammalian outgroups has the potential to identify deeply conserved lineage specification and pluripotency factors, and can extend our understanding of X dosage compensation. Metatherian (marsupial) mammals diverged from eutherians around 160 million years ago. They exhibit distinctive developmental features, including late implantation1 and imprinted X chromosome inactivation2, which is associated with expression of the XIST-like noncoding RNA RSX3. Here we perform a single-cell RNA-sequencing analysis of embryogenesis and X chromosome inactivation in a marsupial, the grey short-tailed opossum (Monodelphis domestica). We resolve the developmental trajectory and transcriptional signatures of the epiblast, primitive endoderm and trophectoderm, and identify deeply conserved lineage-specific markers that pre-date the eutherian–marsupial divergence. RSX coating and inactivation of the X chromosome occurs early and rapidly. This observation supports the hypothesis that—in organisms with early X chromosome inactivation—imprinted X chromosome inactivation prevents biallelic X silencing. We identify XSR, an RSX antisense transcript expressed from the active X chromosome, as a candidate for the regulator of imprinted X chromosome inactivation. Our datasets provide insights into the evolution of mammalian embryogenesis and X dosage compensation. Single-cell RNA-sequencing analysis of embryogenesis and X chromosome inactivation in the opossum (Monodelphis domestica) resolves the developmental trajectory of a marsupial, and sheds light on the evolution of embryogenesis in mammals.
DOI: 10.1038/s41586-020-2629-6
Source: https://www.nature.com/articles/s41586-020-2629-6