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Multiprotein complex formation on the c‐myc promoter
Author(s) -
Logan Thomas J.,
Moberg Kenneth H.,
Hall David J.
Publication year - 1997
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216549700204761
Subject(s) - e2f , transcription factor , multiprotein complex , retinoblastoma protein , chemistry , transcription (linguistics) , e2f1 , microbiology and biotechnology , biology , cell cycle , gene , biochemistry , linguistics , philosophy
The E2F element is a cis‐acting DNA sequence within the P2 promoter of the c‐myc proto‐oncogene. While it is required for optimal transcription, the multiprotein complexes formed on this site have not been well characterized. We show that in extracts of human glioblastoma cells and NIH3T3 fibroblasts, significant E2F transcription factor binding to the c‐myc E2F site occurs as a both a monomer (the active form) and as only two mutually exclusive complexes with the retinoblastoma gene product (pRb) or the cyclin A protein. The E2F protein monomer was found predominantly in the cytosolic fraction of the cellular extracts while the pRb and cyclin A complexes in the nuclear fraction, indicating that the monomer has novel physical properties. Thus, protein complex formation on the c‐myc E2F site appears to contribute in a unique way to transcriptional activation.