Znf706 regulates germ plasm assembly and primordial germ cell development in zebrafish

The cell fate of primordial germ cells (PGCs) in zebrafish is pre-determined by maternally deposited germ plasm, which is packaged into ribonucleoprotein complex in oocytes and inherited into PGCs-fated cells in embryos. However, the maternal factors regulating the assembly of germ plasm and PGC development remain poorly understood. In this study, we report that the maternal transcription factor Znf706 regulates the assembly of germ plasm factors into a granule-like structure localized perinuclearly in PGCs during migration. Maternal and zygotic mutants of znf706 (MZznf706) exhibit deficient germ plasm scattering at the early embryonic stage, decreased PGC numbers with some mislocation during PGC migration, and a lower female ratio in adulthood. Notably, the implementation of Znf706 CUT&Tag and RNA-seq on immature oocytes uncovers that Znf706 in stage I oocytes may promote transcription of several mitochondrial genes in addition to other functions. Hence, we propose that Znf706 is implicated in germ plasm assembly and PGC development in zebrafish.