The catalytic activity of TET1 is required for human germ cell fate choice [bACE-Seq]

Primordial germ cell (PGC) is the foundation of the germline which become gametes and transmit genetic and epigenetic information to the next generation. The segregation of germline and soma is critical yet well-characterized in human during embryonic development due to ethical consideration. Here we discover that human TET1 (Ten-eleven translocation 1) acts as a safety check of germline cell fate. Using CRISPR/Cas9 to knock-out TET1 catalytic domain, we demonstrate extremely low hPGCLC (hPGC-like cell) competency of undifferentiated pluripotent stem cell lines. We plot whole-genome 5’hydroxymethylation (5hmC) profiles to elucidate global as well as locus-specific 5hmC enrichment in hPGCLCs, indicating the DNA oxygenase activity of TET1 is active during hPGCLC differentiation. We applied bisulfite apobec-coupled epigenetic sequencing (bACEseq) in hESC and hPGCLC in 2 cell lines (UCLA1 and UCLA2) and TET1 CDKO hESC (UCLA1) with replicates to measure genome-wide 5-hydroxymethyation (5hmC) level.