Regulation of cyclin D1, DNA topoisomerase I, and proliferating cell nuclear antigen promoters during the cell cycle.
Cyclin D1, DNA topoisomerase I, and proliferating cell nuclear antigen (PCNA) are three important cell cycle regulatory proteins. Recently, their promoters have been isolated, thus facilitating molecular analysis of transcriptional control mechanisms of these genes. Transcription of these three promoters in stable K562 transfectants during different cell cycle phases was analyzed after cell cycle synchronization. About 1 kb of 5' flanking region from either cyclin D1 or DNA topoisomerase I gene is sufficient to confer G1- or S-phase-specific transcription activity to chloramphenicol acetyltransferase (CAT) reporter genes, respectively. In contrast, 2.8 kb of 5' flanking sequences from the PCNA gene led to constitutive transcription, but the inclusion of a segment of the PCNA gene first intron, which contains evolutionarily conserved sequences, could enhance transcription in G1/S-enriched nuclei. This PCNA intron region contains a binding site recognized by the transcription factor E2F. To test whether this site is functional, we cotransfected PCNA-CAT genes with E2F-1 and DP-1 expression plasmids. Expression of the E2F-1/DP-1 heterodimer activated the CAT gene with the PCNA intron. Therefore, this intron region, involved in transcriptional activation at the cell cycle G1/S boundary, is also E2F inducible.
Lee
H H
HH
Institute of Molecular Biology, Academia Sinica, NanKang, Taipei, Taiwan, Republic of China.
Chiang
W H
WH
Chiang
S H
SH
Liu
Y C
YC
Hwang
J
J
Ng
S Y
SY
D001483:Base Sequence; D002352:Carrier Proteins; D002453:Cell Cycle / Q000235:genetics*; D018797:Cell Cycle Proteins; D002467:Cell Nucleus / Q000235:genetics; D019938:Cyclin D1; D016213:Cyclins / Q000235:genetics*; D004264:DNA Topoisomerases, Type I / Q000235:genetics*; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007438:Introns; D008969:Molecular Sequence Data; D015513:Oncogene Proteins / Q000235:genetics*; D010957:Plasmids; D018809:Proliferating Cell Nuclear Antigen / Q000235:genetics*; D011401:Promoter Regions, Genetic; D056465:Retinoblastoma-Binding Protein 1; D050680:Transcription Factor DP1; D014157:Transcription Factors / Q000494:pharmacology; D014158:Transcription, Genetic
D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D016213:Cyclins; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; D015513:Oncogene Proteins; D018809:Proliferating Cell Nuclear Antigen; D056465:Retinoblastoma-Binding Protein 1; C493735:TFDP1 protein, human; D050680:Transcription Factor DP1; D014157:Transcription Factors; D019938:Cyclin D1; D004264:DNA Topoisomerases, Type I