Enhancement of in vitro transcription of human c-myc correlates with the binding of phosphorylated protein factors from HeLa cell extract.

Hela cell extract overphosphorylated with endogenous protein kinases was used for in vitro transcription of human c-myc DNA. The activation of transcription initiated from P1, P1a and P2 cap-sites was observed. Three phosphoproteins of 70, 35 and 23 kDa are found, whose binding to DNA correlates with activation of c-myc transcription. Sites of binding of these proteins to DNA are located.