Saflund, M.; Askari, M.; Eghbali, A.; Abdi, M. M.; Östlund Farrants, A.-K.; Yu, T.; Ozata, D. M.

Meiotic prophase I characterized by homologous recombination and synapsis is an intricate step for spermatogenesis. This process entails extensive changes to chromatin and transcription. Prior to prophase I, accessible chromatin bound by paused Pol II at meiotic gene promoters is essential for their timely activation later during meiosis. However, the factor responsible for promoting accessible chromatin at meiotic gene promoters before entry into prophase I is unknown. Here, we discovered that NFYA expressed in pre-meiotic germ cells promotes accessible chromatin at meiotic gene promoters including those regulated by STRA8/MEISON axis. Concordantly, conditional germline deletion of Nfya in male mice blocks meiotic entry. Functionally, our spatial and single-cell ATAC-seq data revealed that loss of NFYA in pre-meiotic cells disrupts accessible chromatin at meiotic gene promoters. Our study identifies a pioneer role for NFYA in facilitating accessible chromatin at meiotic gene promoters before meiosis, thereby regulating the timely activation of meiotic genetic program.