Analysis of sex differences in EGC imprinting.
Sex-specific differences are apparent in the methylation patterns of H19 and Igf2 imprinted genes in embryonic germ cells (EGCs) derived from 11.5 or 12.5 days post coitum (dpc) primordial germ cells (PGCs). Here we studied whether these differences are associated either with the sex chromosome constitution of the EGCs or with the sex of the genital ridge (testis versus ovary) from which the PGCs were isolated. For this purpose we derived pluripotent EGC lines from sex-reversed embryos, either XY embryos deleted for Sry (XY(Tdym1)) or XX embryos carrying an Sry transgene. Southern blotting of the EGC DNA was used to analyze the differentially methylated regions of Igf2 and H19. The analysis revealed that both genes were more methylated in EGCs with an XY sex chromosome constitution than in those with an XX sex chromosome constitution, irrespective of the phenotypic sex of the genital ridge from which the EGCs had been derived. We conclude that the sex-specific methylation is intrinsic and cell-autonomous, and is not due to any influence of the genital ridge somatic cells upon the PGCs.
Durcova-Hills
Gabriela
G
The Wellcome Trust/Cancer Research UK Gurdon Institute of Cancer and Developmental Biology, Cambridge CB2 1QR, UK.
Burgoyne
Paul
P
McLaren
Anne
A
D000818:Animals; D015139:Blotting, Southern; D005260:Female; D018392:Genomic Imprinting; D005854:Germ Cells / Q000166:cytology*; D007335:Insulin-Like Growth Factor II / Q000235:genetics; D008297:Male; D016133:Polymerase Chain Reaction; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated / Q000235:genetics; D012737:Sex Factors
C094335:H19 long non-coding RNA; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D007335:Insulin-Like Growth Factor II