ATR expands embryonic stem cell fate potential in response to replication stress

Abstract

Unrepaired DNA damage during embryonic development can be potentially inherited by a large population of cells. However, the quality control mechanisms that minimize the contribution of damaged cells to developing embryos remain poorly understood.Here, we uncovered an ATR-and CHK1-mediated transcriptional response to replication stress (RS) in ESCs that induces genes expressed in totipotent two-cell (2C) stage embryos and 2C-like cells. This response is mediated by Dux, a multicopy retrogene defining the cleavage-specific transcriptional program in placental mammals. In response to RS, DUX triggers the transcription of 2C-like markers such as murine endogenous retrovirus-like elements (MERVL) and Zscan4. This response can also be elicited by ETAA1-mediated ATR activation in the absence of RS. ATR-mediated activation of DUX requires GSRF1 dependent post-transcriptional regulation of Dux mRNA. Strikingly, activation of ATR expands ESCs fate potential by extending their contribution to both embryonic and extraembryonic tissues. These findings define a novel ATR dependent pathway involved in maintaining genome stability in developing embryos by controlling ESCs fate in response to RS. BackgroundESCs are characterized by self-renewal and the ability to propagate for several cycles in vitro and in vivo 1 . Even if ESCs exhibit several markers of RS 2 , they are able to maintain genome integrity more efficiently than differentiated cells 1 . The mechanisms underlying such distinctive feature are largely unknown. ESC colonies harbor a small transient subpopulation of cells (2C-like cells) with functional andtranscriptional features of totipotent 2C-stage embryos 3-5 . Transition to 2C-like cells has been shown to promote maintenance of genome integrity and survival of ESCs in long-term culture 6-8 . In addition, several studies have demonstrated that transition to the 2C-like state confers expanded developmental potential to ESCs, making them capable of contributing to both embryonic and extra-embryonic tissues (also referred to as bidirectional cell fate potential) 3-5 . However, the molecular players underlying the transition to the 2C-like state in ESC culture and its possible physiological relevance in vivo in maintaining genome integrity and expanding cell fate potential in a developing embryo are not fully understood.Here we provide several lines of evidence that ATR and CHK1-mediated response to RS triggers the activation of 2C-specific genes in ESCs and mouse embryos. This transition is hampered in ESCs derived from ATR-deficient Seckel and CHK1 haploinsufficient mouse models and following ATR or CHK1 inhibition. Significantly, we show that ETAA1-mediated ATR activation is sufficient to trigger the formation of 2C-like cells in the absence of RS.Mechanistically, ATR-induced transition to 2C-like state is mediated by post-transcriptional regulation of the Dux gene, which shapes the transcriptional signature of 2C-like cells and totipotent 2C-stage embryos in placental mammals 9-11 . ATR-dependent regulation of Du...

Nsd2 Represses Endogenous Retrovirus MERVL in Embryonic Stem Cells

“…It is recently discovered that DNA damage is induced by the depletion of MERVL activator Zscan4 [ 3 , 31 ]. Responses of ATR and CHK1 to replication stresses activate Zscan4 and MERVL [ 20 ], implying that DNA damage-induced replication stress and Zscan4 reciprocally regulate each other. It will be interesting to investigate whether Nsd2 is involved DNA damage repair and its relationship with Zscan4 in the future.…”

“…Total RNA was isolated from cells by RNAiso Reagent (B9109, Takara) in DEPC water (B501005, Sangon Biotech) following by DNase I treatment in RNase-free tubes (401001, NEST Biotechnology). Reverse transcription was performed with 1 μ g purified RNA using Transcriptor First Strand cDNA Synthesis Kit (4897030001, Roche) as described previously [ 20 ]. qPCR analysis was carried out using SYBR Green qPCR Master Mix (H97410, Yeasen) and a qPCR detection system (CFX384 Real-Time System, Bio-Rad) according to standard protocols.…”

The Rna-binding Protein GRSF1 Promote shepatocarcinogenesis via competitively Binding Toyy1 mRNA with mIR-30e-5p

“…In addition, recent research suggested that VE-821 showed a synergistic effect with PD-L1 inhibition in pancreatic cancer, and PD-L1 inhibition increased VE-821 sensitivity [40] . GRSF1 is necessary in the progression of ATR-dependent regulation on Dux, which is vital for the cleavage-speci c transcription [41] .Therefore, whether the combination with PD-L1 inhibition could improve antitumor function of VE-821 on HCC induced by GRSF1 is worth to be further discussed in the future.…”

A developmentally programmed splicing failure attenuates the DNA damage response during mammalian zygotic genome activation

“…Consistently, it has been reported that mouse embryos are particularly sensitive to the replication stress agent aphidicolin during ZGA 47 . Moreover, ATR, but not ATM, was recently shown to be required for the conversion of mouse embryonic stem cells into 2C-like cells, which are characterized by the activation of various ZGA markers 48 . Thus, hampering DDR through ATM but not ATR pathway could allow lowering the tolerance for DNA damage whilst ensuring genome stability during ZGA.…”