Comparison of Zfp706GT and ZfpGT REV ES cells in 2i

Self-renewal circuitry in embryonic stem (ES) cells is increasingly defined. How the robust pluripotency programme is dissolved to enable fate transition is less appreciated. We developed a forward genetic approach using haploid ES cells. We created libraries of transposon integrations and screened for persistent self-renewal in differentiation permissive culture. This yielded multiple mutants in the FGF/Erk and GSK3/Tcf3 modules known to drive differentiation, and in epigenetic modifiers implicated in lineage commitment. We also identified and validated factors not previously considered. These include the conserved small zinc finger protein Zfp706. Loss of Zfp706 function severely delays the exit from self-renewal. To asses a potential function of Zfp706 in regulation of gene expression we compared transcription profiles between Zfp706 gene trap mutant ES cells and genetic revertants. Assessment of differentially expressed genes in Zfp706 gene trap mutants obtained in a haploid ES cell screen for effectors of ES cell differentiation vs. genetic revertants generated by Flp-e mediated excision of the gene trap cassette