The origin of sex reversal in XX goats homozygous for the polled intersex syndrome (PIS) mutation was unclear because of the complexity of the mutation that affects the transcription of both FOXL2 and several long noncoding RNAs (lncRNAs). Accumulating evidence suggested that FOXL2 could be the sole gene of the PIS locus responsible for XX sex reversal, the lncRNAs being involved in transcriptional regulation of FOXL2. In this study, using zinc-finger nuclease-directed mutagenesis, we generated several fetuses, of which one XX individual bears biallelic mutations of FOXL2. Our analysis demonstrates that FOXL2 loss of function dissociated from loss of lncRNA expression is sufficient to cause an XX female-to-male sex reversal in the goat model and, as in the mouse model, an agenesis of eyelids. Both developmental defects were reproduced in two newborn animals cloned from the XX FOXL2(-/-) fibroblasts. These results therefore identify FOXL2 as a bona fide female sex-determining gene in the goat. They also highlight a stage-dependent role of FOXL2 in the ovary, different between goats and mice, being important for fetal development in the former but for postnatal maintenance in the latter.

Pluripotency genes are implicated in mouse embryonic genome activation (EGA) and pluripotent lineage specification. Moreover, their expression levels have been correlated with embryonic term development. In bovine, however, little information is available about dynamics of pluripotency genes during these processes. In this study, we charted quantitative and/or qualitative spatio-temporal expression patterns of transcripts and proteins of pluripotency genes (OCT4, SOX2 and NANOG) and mRNA levels of some of their downstream targets in bovine oocytes and early embryos. Furthermore, to correlate expression patterns of these genes with term developmental potential, we used cloned embryos, having similar in vitro but different full term development rates. Our findings affirm: firstly, the core triad of pluripotency genes is probably not implicated in bovine EGA since their proteins were not detected during pre-EGA phase, despite the transcripts for OCT4 and SOX2 were present. Secondly, an earlier ICM specification of transcripts and proteins of SOX2 and NANOG makes them pertinent candidates of bovine pluripotent lineage specification than OCT4. Thirdly, embryos with low term development potential have higher transcription rates; nevertheless, precarious balance between pluripotency genes is maintained. This balance presages normal in vitro development but, probably higher transcription rate disturbs it at later stage that abrogates term development.

Vitellogenic oocytes and eggs of the frog Xenopus laevis contain intermediate-size filaments that are resistant to extractions in high-salt buffers and Triton X-100 and are specifically stained with antibodies to cytokeratins. Gel electrophoresis of cytoskeletal proteins from Xenopus oocytes shows a specific enrichment of three polypeptides designated components 1 [Mr, 56,

(2012) Analysis of active chromatin modifications in early mammalian embryos reveals uncoupling of H2A.Z acetylation and H3K36 trimethylation from embryonic genome activation, Epigenetics,7:7,[747][748][749][750][751][752][753][754][755][756][757]