Participation of cyclin A in Myc-induced apoptosis.
The involvement of c-Myc in cellular proliferation or apoptosis has been linked to differential cyclin gene expression. We observed that in both proliferating cells and cells undergoing apoptosis, cyclin A (but not B, C, D1, and E) mRNA level was elevated in unsynchronized Myc-overexpressing cells when compared with parental Rat1a fibroblasts. We further demonstrated that Zn(2+)-inducible cyclin A expression was sufficient to cause apoptosis. When Myc-induced apoptosis was blocked by coexpression of Bcl-2, the levels of cyclin C, D1, and E mRNAs were also elevated. Thus, while apoptosis induced by c-Myc is associated with an elevated cyclin A mRNA level, protection from apoptosis by coexpressed Bcl-2 is associated with a complementary increase in cyclin C, D1, and E mRNAs.
Hoang
A T
AT
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205.
Cohen
K J
KJ
Barrett
J F
JF
Bergstrom
D A
DA
Dang
C V
CV
D000818:Animals; D017209:Apoptosis; D002455:Cell Division; D002460:Cell Line; D016213:Cyclins / Q000235:genetics / Q000502:physiology*; D005786:Gene Expression Regulation; D006801:Humans; D016271:Proto-Oncogene Proteins c-myc / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D014162:Transfection; D015032:Zinc / Q000494:pharmacology
D016213:Cyclins; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D015032:Zinc