Abstract:

Objective To identify novel genes promoting trophoblastic differentiation in mouse embryonic stem (ES) cells. Methods Inducing conditions for trophoblastic differentiation in mouse ES cells were optimized. Combined with data analysis, significantly upregulated genes during this differentiation process were identified and singlestrandedDNA binding protein 2 (Ssbp2) was discovered as a candidate gene involved in trophoblastic differentiation. Changes in Ssbp2 expression during the process of trophoblastic differentiation in mouse ES cells, as well as expression patterns of Ssbp2 in three cell types corresponding to early mouse embryos, were detected by qRT-PCR. Then Ssbp2 genes were cloned and overexpressed in mouse ES cells. Cell morphology was observed and whether Ssbp2 genes could promote trophoblastic differentiation in mouse ES cells was detected. Results Through trials with different combinations, we found serumfree mouse TS cell basic medium with BMP4 and bFGF could not only induce significant upregulation of trophoblast markers in mouse ES cells, but also efficiently repress the up-regulation of mesoderm markers. Expression pattern analysis showed that the expression level of Ssbp2 was significantly up-regulated during the process of inducing trophoblastic differentiation in mouse ES cells and Ssbp2 expression was high in mouse trophoblastic TS cells. After overexpression of Ssbp2 in mouse ES cells, ES cells were partially differentiated and the up-regulation in trophoblastic markers was most significant. Conclusion Ssbp2 can promote trophoblastic differentiation in mouse ES cells.

Key words: embryonic stem cell, trophoblast, differentiation, Ssbp2