Sex-specific chromatin states in mammalian fetal germ cells

Bluma J Lesch,David C Page

doi:10.1186/1756-8935-6-s1-p45

Bluma J Lesch, David C Page

Open Access

https://doi.org/10.1186/1756-8935-6-s1-p45

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Abstract

Background Male and female mammalian germ cells follow identical developmental trajectories for the first half of embryogenesis, during which time they also maintain a pluripotentlike state. Beginning around day 13.5 of embryogenesis (E13.5), male and female germ cells initiate dramatically different developmental programs: female germ cells enter meiotic prophase, while male germ cells enter a G0-like cell cycle arrest until after birth [1]. At this time, both male and female germ cells also lose the ability to establish pluripotent cell lines in culture [2]. As late as E12.5, male and female germ cells are morphologically identical, and few transcriptional differences can be detected [1,3]. To evaluate the coordination of sex-specific transcriptional states during this important interval in germ cell differentiation, we examined placement of the activating histone modification H3K4me3 and the repressive histone modification H3K27me3 in XX and XY murine germ cells before and during the initiation of sex differentiation.

Highlights

Male and female mammalian germ cells follow identical developmental trajectories for the first half of embryogenesis, during which time they maintain a pluripotentlike state
Materials and methods Germ cells expressing an Oct4-EGFP transgene [4] were isolated by flow cytometry from male and female mouse embryos at 12.5 or 13.5 days post coitus
ChIP-seq data was compared to preexisting RNA-seq data from E12.5 or E14.5 male and female gonads

Summary

Background

Male and female mammalian germ cells follow identical developmental trajectories for the first half of embryogenesis, during which time they maintain a pluripotentlike state. Beginning around day 13.5 of embryogenesis (E13.5), male and female germ cells initiate dramatically different developmental programs: female germ cells enter meiotic prophase, while male germ cells enter a G0-like cell cycle arrest until after birth [1]. At this time, both male and female germ cells lose the ability to establish pluripotent cell lines in culture [2]. As late as E12.5, male and female germ cells are morphologically identical, and few transcriptional differences can be detected [1,3]. To evaluate the coordination of sex-specific transcriptional states during this important interval in germ cell differentiation, we examined placement of the activating histone modification H3K4me[3] and the repressive histone modification H3K27me[3] in XX and XY murine germ cells before and during the initiation of sex differentiation

Materials and methods

Conclusions

McLaren A

Results