Embryonic lethality and defective male germ cell development in mice lacking UTF1

The germ cell lineage is specified early in embryogenesis and undergoes complex developmental programs to generate gametes. Here, we conducted genetic studies to investigate the role of Utf1 (Undifferentiated embryonic cell transcription factor 1) in mouse germ cell development. Utf1 is expressed in pluripotent embryonic stem (ES) cells and regulates ES cell differentiation. In a proteomics screen, we identified UTF1 among 38 proteins including DNMT3L and DND1 that associate with chromatin in embryonic testes. We find that UTF1 is expressed in embryonic and newborn gonocytes and in a subset of early spermatogonia. Ubiquitous inactivation of Utf1 causes embryonic lethality in mice with a hybrid genetic background. Male mice with a germline-specific deletion of Utf1 resulting from Prdm1-Cre mediated recombination are born with significantly fewer gonocytes and exhibit defective spermatogenesis and reduced sperm count as young adults. These defects are ameliorated in older animals. These results demonstrate that UTF1 is required for embryonic development and regulates male germ cell development.