Braun, T.T.BraunGearing, K.K.GearingWright, W.E.W.E.WrightArnold, H.-H.H.-H.Arnold2022-03-032022-03-031991https://publica.fraunhofer.de/handle/publica/17968410.1111/j.1432-1033.1991.tb16000.xTwo recombinant baculoviruses BcV-myf4 and BcV-myf5 have been constructed to synthesize the human myogenic determination factors myogenin (myf4) and myf5 in eucaryotic cells. Both recombinant proteins are localized to the nucleus of virus-infected Spodoroptera frugiperda (sf) insect cells and can be recovered as soluble factors. The virus-produced proteins exhibit high-affinity binding to a muscle-specific DNA sequence in the presence of the ubiquitous helix-loop-helix (HLH) protein E12, but only marginal binding in unsupplemented sf nuclear extracts. Both baculovirus-encoded myogenic factors are able to heterooligomerize with E12 in the absence of DNA-binding sites. We conclude from our results that these muscle-specific HLH proteins produced in eucaryotic cells largely depend on dimerization with E12 or similar HLH proteins to recognize the myosin-light-chain-enhancer-MEF-1-binding site. We have no evidence for intracellular protein modifications exerting major effects on the interac tion between these factors and DNA.enbaculoviridaegene expressiongeneticgenetic transcriptionmusclemuscle proteinmyosinregulation615610620journal article