Early X chromosome inactivation during human preimplantation development revealed by single-cell RNA-sequencing

Author(s)

Moreira de Mello, Joana C. ; Fernandes, Gustavo R. ; Vibranovski, Maria D. ; Pereira, Lygia V.

• Document type: Journal article
• Source: SCIENTIFIC REPORTS; v. 7, SEP 7 2017.
• Web of Science Citations: 21

Abstract

In female mammals, one X chromosome is transcriptionally inactivated (XCI), leading to dosage compensation between sexes, fundamental for embryo viability. A previous study using single-cell RNA-sequencing (scRNA-seq) data proposed that female human preimplantation embryos achieve dosage compensation by downregulating both Xs, a phenomenon named dampening of X expression. Using a novel pipeline on those data, we identified a decrease in the proportion of biallelically expressed X-linked genes during development, consistent with XCI. Moreover, we show that while the expression sum of biallelically expressed X-linked genes decreases with embryonic development, their median expression remains constant, rejecting the hypothesis of X dampening. In addition, analyses of a different dataset of scRNA-seq suggest the appearance of X-linked monoallelic expression by the late blastocyst stage in females, another hallmark of initiation of XCI. Finally, we addressed the issue of dosage compensation between the single active X and autosomes in males and females for the first time during human preimplantation development, showing emergence of X to autosome dosage compensation by the upregulation of the active X chromosome in both male and female embryonic stem cells. Our results show compelling evidence of an early process of X chromosome inactivation during human preimplantation development. (AU)

• FAPESP's process: 15/20844-4 - The role of gametogenesis on the origin and evolution of new genes
• Grantee: Maria Dulcetti Vibranovski
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 09/17481-6 - X-chromosome inactivation in humans: initiation and imprinting
• Grantee: Joana Carvalho Moreira de Mello
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 13/08135-2 - CTC - Center for Cell-Based Therapy
• Grantee: Dimas Tadeu Covas
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 15/03610-0 - In silico analysis of the X-chromosome epigenetic state in human pre-implantation embryos
• Grantee: Joana Carvalho Moreira de Mello
• Support Opportunities: Scholarships in Brazil - Post-Doctoral