Molecular cloning of gene sequences that are regulated by insulin-like growth factor I.
Insulin-like growth factor I (IGF I) regulates the expression of a select few genes in quiescent BALB/c-3T3 cells. This was demonstrated by gel electrophoresis of radiolabeled proteins and by molecular cloning of twelve distinct IGF I-regulated cDNAs. Together, the electrophoretic and cloning data show that IGF I stimulates the expression of about 0.15% of the genes expressed by 3T3 cells, perhaps 30 genes in total. The genes encode both cytoplasmic and nuclear proteins. At the regulatory level the IGF I-controlled genes segregate into two categories. Category I genes (the minority) respond preferentially to IGF I. Their induction is prevented by actinomycin D, and they are superinduced by the combination of IGF I and anisomycin. Category II genes (the majority) respond to platelet-derived growth factor as well as to IGF I. The response of category II genes to IGF I is insensitive to actinomycin D. The data indicate that category II genes are constitutively transcribed and that IGF I regulates stability of the transcripts. The expression of category II genes correlates well with the ability of 3T3 cells to survive in serum-free culture medium.
D000818:Animals; D000841:Anisomycin / Q000494:pharmacology; D002460:Cell Line; D002470:Cell Survival; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D003609:Dactinomycin / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D005786:Gene Expression Regulation; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D013002:Somatomedins / Q000494:pharmacology*; D014158:Transcription, Genetic
D010982:Platelet-Derived Growth Factor; D012333:RNA, Messenger; D013002:Somatomedins; D003609:Dactinomycin; D007334:Insulin-Like Growth Factor I; D000841:Anisomycin; D004247:DNA