E2F-1 has dual roles depending on the cell cycle.
The E2F family of transcription factors play a critical role in the control of cell proliferation. E2F-1 is the major cellular target of pRB and is regulated by pRB during cell proliferation. E2F-1-mediated activation and repression of target genes occurs in different settings. The role of E2F-1 and E2F-1/pRB complexes in regulation of different target genes, and in cycling versus quiescent cells, is unclear. In this study, effects of free E2F-1 (doesn't complex with pRb) and E2F-1/pRb complex, on E2F-1 target gene expression were compared in different cell growth conditions. Findings suggest that E2F-1 acts in different ways, not only depending on the target gene but also depending on different stages of the cell cycle. For example, E2F-1 acts as part of the repression complex with pRB in the expression of DHFR, b-myb, TK and cdc2 in asynchronously growing cells; on the other hand, E2F-1 acts as an activator in the expression of the same genes in cells that are re-entering the cycle.
Department of Microbiology and Immunology, Finch University of Health Sciences/Chicago Medical School (now Rosalind Franklin University), 3333 Green Bay Road, North Chicago, Illinois 60064-3095, USA. fsahin29@hotmail.com
Fikret
F
Sahin
Todd L
TL
Sladek
D000818:Animals; D016203:CDC2 Protein Kinase / Q000378:metabolism; D002453:Cell Cycle; D002460:Cell Line; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D017931:DNA Primers / Q000737:chemistry; D050687:E2F1 Transcription Factor / Q000378:metabolism / Q000502:physiology*; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D051379:Mice; D008954:Models, Biological; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000378:metabolism
D017931:DNA Primers; D050687:E2F1 Transcription Factor; C493754:E2f1 protein, mouse; D014157:Transcription Factors; D016203:CDC2 Protein Kinase
Cell cycle; E2F-1; Rb; TK; cdc2; cmyc; dhfr