CDF-1, a novel E2F-unrelated factor, interacts with cell cycle-regulated repressor elements in multiple promoters.
The cdc25C , cdc2 and cyclin A promoters are controlled by transcriptional repression through two contiguous protein binding sites, termed the CDE and CHR. In the present study we have identified a factor, CDF-1, which interacts with the cdc25C CDE-CHR module. CDF-1 binds to the CDE in the major groove and to the CHR in the minor grove in a cooperative fashion in vitro , in a manner similar to that seen by genomic footprinting. In agreement with in vivo binding data and its putative function as a periodic repressor, DNA binding by CDF-1 in nuclear extracts is down-regulated during cell cycle progression. CDF-1 also binds avidly to the CDE-CHR modules of the cdc2 and cyclin A promoters, but not to the E2F site in the B- myb promoter. Conversely, E2F complexes do not recognize the cdc25C CDE-CHR and CDF-1 is immunologically unrelated to all known E2F and DP family members. This indicates that E2F- and CDF-mediated repression is controlled by different factors acting at different stages during the cell cycle. While E2F-mediated repression seems to be associated with genes that are up-regulated early (around mid G1), such as B- myb , CDE-CHR-controlled genes, such as cdc25C , cdc2 and cyclin A , become derepressed later. Finally, the fractionation of native nuclear extracts on glycerol gradients leads to separation of CDF-1 from both E2F complexes and pocket proteins of the pRb family. This emphasizes the conclusion that CDF-1 is not an E2F family member and points to profound differences in the cell cycle regulation of CDF-1 and E2F.
Liu
N
N
Institut für Molekularbiologie und Tumorforschung (IMT), Philipps-Universität Marburg Emil-Mannkopff-Strasse 2, D-35033 Marburg, Germany.
Lucibello
F C
FC
Körner
K
K
Wolfraim
L A
LA
Zwicker
J
J
Müller
R
R
D016475:3T3 Cells; D000818:Animals; D016203:CDC2 Protein Kinase / Q000096:biosynthesis / Q000235:genetics*; D002352:Carrier Proteins; D002453:Cell Cycle / Q000235:genetics*; D018797:Cell Cycle Proteins / Q000096:biosynthesis / Q000235:genetics*; D019925:Cyclin A / Q000096:biosynthesis / Q000235:genetics*; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000502:physiology*; D050684:E2F Transcription Factors; D005786:Gene Expression Regulation / Q000235:genetics*; D046911:Macromolecular Substances; D051379:Mice; D010749:Phosphoprotein Phosphatases / Q000096:biosynthesis / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000502:physiology*; D056465:Retinoblastoma-Binding Protein 1; D050680:Transcription Factor DP1; D014157:Transcription Factors / Q000378:metabolism; D014162:Transfection; D020687:cdc25 Phosphatases
C533431:Arid4a protein, mouse; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D019925:Cyclin A; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D046911:Macromolecular Substances; D012097:Repressor Proteins; D056465:Retinoblastoma-Binding Protein 1; D050680:Transcription Factor DP1; D014157:Transcription Factors; D016203:CDC2 Protein Kinase; D010749:Phosphoprotein Phosphatases; D020687:cdc25 Phosphatases