Imprinted genes play important roles in placenta development and function. Parthenogenetic embryos, deficient in paternally expressed imprinted genes, lack extra-embryonic tissues of the trophoblast lineage. Parthenogenetic trophoblast stem cells (TSCs) are extremely difficult to derive, suggesting that an imprinted gene(s) is necessary for TSC establishment or maintenance. In a candidate study, we were able to narrow the list to one known paternally expressed gene, Sfmbt2. We show that mouse embryos inheriting a paternal Sfmbt2 gene trap null allele have severely reduced placentae and die before E12.5 due to reduction of all trophoblast cell types. We infected early embryos with lentivirus vectors expressing anti-Sfmbt2 shRNAs and found that TSC derivation was significantly reduced. Together, these observations support the hypothesis that loss of SFMBT2 results in defects in maintenance of trophoblast cell types necessary for development of the extra-embryonic tissues, the placenta in particular.
Author contributions
K.L. and Z.Z. performed qRT-PCR on blastocysts (Fig. 2). B.P. and A.A. performed FISH (Fig. 1C-F), S.V. performed parthenogenetic TSC derivation (Table 1), genotyping (Table 2), reactivation analysis (Fig. 4), insertion site mapping supplementary material (Fig. S1), MatDup analysis supplementary material (Fig. S5). K.M. performed histology (Figs 3, 5, 6; supplementary material Figs S4, S6), allele-specific expression analysis (Fig. 1; supplementary material Fig. S2), lentivirus knockdown (Fig. 7), qRT-PCR (Fig. 3) and production of anti-SFMBT2 antisera. Manuscript was prepared by K.M. and S.V.
Funding
Funding for this work was provided by grants from the Natural Sciences and Engineering Research Council of Canada (S.V.) and the US National Institutes of Health [HD43092 to K.L.; GM088506 to B.P.]. Deposited in PMC for release after 12 months.
