IGF2BP1 stabilizes OTX2 mRNA in an m6A-dependent manner to restrict human germ cell fate by repressing TFAP2C [CUT&Tag]

N6-methyladenosine (m6A) is the most abundant and reversible modification on messenger RNAs. The differential m6A profiles in different cell types are installed by writers (such as METTL3) and removed by erasers (such as FTO). The m6A-modified RNAs are recognized by readers to trigger downstream regulation of RNA metabolism, eventually contributing to the regulation of cell fates. Primordial germ cells (PGCs) are specified early during embryogenesis and establish the germ cell lineage for transmitting genetic and epigenetic information from parents to offspring. Defects in the establishment of germline may lead to infertility, germ cell tumors, and birth defects. Despite extensive research, the m6A-mediated epigenetic regulation of the specification of PGCs remains elusive. In this study, we discovered that knock-out of m6A writer or over-expression of erasers leads to increased percentage of human PGC-like cells (hPGCLCs) induced from embryonic stem cells. We identified the m6A reader IGF2BP1 as the key factor for restricting hPGCLC fate induction by stabilizing OTX2 mRNAs in an m6A-dependent manner. Moreover, we discovered that OTX2 suppresses TFAP2C during germ cell lineage specification. In summary, we characterized the m6A-IGF2BP1-OTX2-TFAP2C axis in restricting the specification of human germ cell fate.