REPRESSION OF MS_3 GENE EXPRESSION DURING HMBA INDUCED DIFFERENTIATION OF AN EMBRYONAL CARCINOMA CELL LINE, B 7 - 2 IN VITRO
环六亚甲基双乙酰胺体外诱导胚胎性癌B7—2细胞分化对MS_3基因表达的影响

We have cloned a cDNA sequence comprising about 300 nucleotides. This cDNA sequence can detect a RNA species with a size of about 6 kb in the total cellular RNAs and the total poly (A+) RNAs of some mouse embryonal carcinoma (EC) cell lines such as F9, PCC3, PSAl, but not in several differentiated derivatives of EC cells examined so iar, i. e., TDM1 (trophoblastoma cell), PYS-2 (parietal york saclike cell), 3/A/1-D3 (embryonic fibroblast-like cell) and C17-S1-T384 (myoblast-like cell). Therefore we designate this cDNA sequence as multipotent cell specific sequence (MS3 sequence). The amount of MS3 RNA in B7 - 2 cells before and after induction with HMBA was estimated by the technique of dot blot hybridization. Mouse 3T3 cells were employed as a negative control. Induction with HMBA for 5 days brought about 86% reduction of the amount of MS3 RNA in B7-2 cells. Since the induction effeciency was about 90%, it is evident that the expression of MS3 gene was repressed in the induced differentiated derivatives of B7 - 2 cells.