Baculovirus-expressed myogenic determination factors require E12 complex formation for binding to the myosin-light-chain enhancer.
Two 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 interaction between these factors and DNA.
Braun
T
T
Department of Toxicology, Medical School, University of Hamburg, Federal Republic of Germany.
Gearing
K
K
Wright
W E
WE
Arnold
H H
HH
D016367:Baculoviridae / Q000235:genetics*; D015153:Blotting, Western; D004268:DNA-Binding Proteins; D004591:Electrophoresis, Polyacrylamide Gel; D015967:Gene Expression Regulation, Viral; D005814:Genes, Viral; D006801:Humans; D007150:Immunohistochemistry; D009124:Muscle Proteins / Q000235:genetics*; D051787:Myogenic Regulatory Factor 5; D018008:Myogenin; D009218:Myosins / Q000378:metabolism*; D011233:Precipitin Tests; D014176:Protein Biosynthesis; D015534:Trans-Activators; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; C497417:MYF5 protein, human; C503799:MYOG protein, human; D009124:Muscle Proteins; D051787:Myogenic Regulatory Factor 5; D018008:Myogenin; D015534:Trans-Activators; D009218:Myosins