[Studies on the phenotypic differences of P68 RNA helicases in four cell lines]

The dynamic changes of P68 RNA helicases derived from four cell lines were compared on the level of proteins and mRNAs. Of the four cell lines, HeLa and TC3H10 are tumouric while NIH 3T3 and NC3H10 are nontumouric. The TC3H10 is the derivative of NC3H10 induced by 3H-TdR. The growing curves showed that all of them can reach Logarithum phase around 24 hours post-inoculation. The Western blotting showed that the P68 RNA helicases in cells exhibited some regular patterns along with the extended growth of the cell cultures: they appeared as early as 6 hours post-inoculation, reached to the top about 24 hours, and dropped and maintained to low level after then. During a whole passage the bands of P68 RNA helicases were only single in tumour cells but multiple in nontumour cells with moderate changes. RNA slot hybridization resulted in similar quantitative patterns of P68 mRNAs and its proteins in each line. The ATPase activities of P68 RNA helicases purified by McAb-PAb 204 mediated immunoprecipitation were ssRNA-dependent, consistent with the results of P68 RNA helicases reported by others. These results first showed the close relationship between P68 RNA helicase and cell growth on the molecular level, and maybe implied its potential functions in the cell transformation process.