ATF site of human RB gene promoter is a responsive element of myogenic differentiation.
RB mRNA increases during terminal differentiation of C2 myoblasts. We demonstrate that RB promoter activity increases about 4-fold during differentiation. The increase of RB promoter activity was reduced when a point mutation was designed in the ATF site. In a gel shift assay of the ATF site, two specific bands were observed. One of them, with the lower mobility, disappeared during differentiation. This band reacted with an antibody against ATF-1. We cotransfected an RB promoter-luciferase plasmid with the TREB36/ATF-1 plasmid. ATF-l suppressed the activity of the wild-type RB promoter but not of that with a point mutation at the ATF site. These results suggest that the ATF site of the RB promoter is a responsive element during myogenic differentiation of C2 cells. We hypothesize that RB promoter activity is stimulated partially due to the dissociation of ATF-1, which suppresses the promoter activity through the ATF site in C2 myoblasts.
Okuyama
Y
Y
Department of Preventive Medicine, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Japan.
Sowa
Y
Y
Fujita
T
T
Mizuno
T
T
Nomura
H
H
Nikaido
T
T
Endo
T
T
Sakai
T
T
D051697:Activating Transcription Factor 1; D000818:Animals; D001665:Binding Sites; D002454:Cell Differentiation; D002460:Cell Line; D016213:Cyclins / Q000235:genetics; D004268:DNA-Binding Proteins; D016161:Genes, Retinoblastoma; D006801:Humans; D051379:Mice; D018482:Muscle, Skeletal / Q000166:cytology*; D017354:Point Mutation; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000378:metabolism*; D015854:Up-Regulation
D051697:Activating Transcription Factor 1; C497100:Atf1 protein, mouse; D016213:Cyclins; D004268:DNA-Binding Proteins; D014157:Transcription Factors