TY - JOUR
T1 - Ssm1b expression and function in germ cells of adult mice and in early embryos
AU - Ratnam, Sarayu
AU - Bozek, Grazyna
AU - Martin, Terence
AU - Gallagher, Shannon J.
AU - Payne, Christopher J.
AU - Storb, Ursula
N1 - Funding Information:
The authors wish to thank Dan Nicolae, Department of Medicine, University of Chicago for performing the statistical analysis; William Buikema, DNA sequencing facility, University of Chicago for the DNA sequencing; Tara Payton of the Centre for Applied Genomics, The Hospital for Sick Children, Toronto, Canada for assistance with the speed congenics; the Northwestern University—Flow Cytometry Core Facility supported by Cancer Center Support Grant (NCI CA060553) for FACS analysis and cell sorting; Francesca Duncan for her help with oocyte collection from the ovaries; and Peter Engler for critical review of the manuscript. The studies were supported by National Institutes of Health (NIH) grants (RO3HD05827 and AI047380) and a Pilot Project grant from the University of Chicago Cancer Research Center to U.S. Support for S.R was by a fellowship from the Cancer Research Institute. C.P. is funded BY NIH grant U01HD084046. The authors declare no conflict of interest.
Publisher Copyright:
© 2017 Wiley Periodicals, Inc.
PY - 2017/7
Y1 - 2017/7
N2 - Ssm1b (Strain-specific modifier of DNA methylation 1b) is a Krüppel-associated box (KRAB) zinc finger gene that promotes CpG methylation in the mouse transgene HRD (Heavy chain enhancer, rearrangement by deletion). We report here that Ssm1b expression and concomitant HRD methylation are also present in the male and female germ cells of adult mice. Ssm1b is expressed in both diploid (2N) and haploid (1N) oocytes, as well as in 1N spermatids and spermatozoa, but not in 2N spermatogonia. Interestingly, Ssm1b mRNA is not detected in any other adult mouse organ examined, although Ssm1-family mRNAs are highly expressed in the heart. Reflecting strain specificity, Ssm1b expression and HRD methylation are not observed in early-stage C3H/HeJ mouse embryos; however, an Ssm1b-like gene that closely resembles an Ssm1b-like gene previously found in wild-derived mice is expressed in cultured embryonic stem cells derived from C3H/HeJ embryos, suggesting that culture conditions affect its expression. Collectively, this work demonstrates that HRD methylation by Ssm1b is more temporally restricted during spermatogenesis compared to oogenesis, and is altered when embryonic stem cells are cultured from C3H/HeJ inner cell mass cells.
AB - Ssm1b (Strain-specific modifier of DNA methylation 1b) is a Krüppel-associated box (KRAB) zinc finger gene that promotes CpG methylation in the mouse transgene HRD (Heavy chain enhancer, rearrangement by deletion). We report here that Ssm1b expression and concomitant HRD methylation are also present in the male and female germ cells of adult mice. Ssm1b is expressed in both diploid (2N) and haploid (1N) oocytes, as well as in 1N spermatids and spermatozoa, but not in 2N spermatogonia. Interestingly, Ssm1b mRNA is not detected in any other adult mouse organ examined, although Ssm1-family mRNAs are highly expressed in the heart. Reflecting strain specificity, Ssm1b expression and HRD methylation are not observed in early-stage C3H/HeJ mouse embryos; however, an Ssm1b-like gene that closely resembles an Ssm1b-like gene previously found in wild-derived mice is expressed in cultured embryonic stem cells derived from C3H/HeJ embryos, suggesting that culture conditions affect its expression. Collectively, this work demonstrates that HRD methylation by Ssm1b is more temporally restricted during spermatogenesis compared to oogenesis, and is altered when embryonic stem cells are cultured from C3H/HeJ inner cell mass cells.
KW - DNA methylation
KW - ES cells
KW - KRAB zinc finger gene
UR - http://www.scopus.com/inward/record.url?scp=85020164314&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85020164314&partnerID=8YFLogxK
U2 - 10.1002/mrd.22826
DO - 10.1002/mrd.22826
M3 - Article
C2 - 28464323
AN - SCOPUS:85020164314
SN - 1040-452X
VL - 84
SP - 596
EP - 613
JO - Molecular Reproduction and Development
JF - Molecular Reproduction and Development
IS - 7
ER -