A novel proximal element mediates the regulation of mouse Ren-1C promoter by retinoblastoma protein in cultured cells.
The protein product of the retinoblastoma susceptibility gene, RB, is a nuclear phosphoprotein that modulates transcription of genes involved in growth control via interactions with transcription factors. Renin is a rate-limiting enzyme of the renin-angiotensin system that regulates blood pressure and water-electrolyte balance. Renin gene expression is regulated in a tissue-specific and developmentally linked manner. Similarly, the expression of RB is controlled in a differentiation-linked manner. Thus, to investigate whether RB is involved in the regulation of renin gene expression, we examined the effects of RB on transcriptional activity of the mouse renin (Ren-1C) promoter. The Ren-1C promoter contains two transcriptionally important elements; the RU-1 (-224 to -138) and RP-2 (-75 to -47) elements. RB activated the Ren-1C promoter in human embryonic kidney cells. The promoter element responsible for RB-mediated transcriptional regulation was the RP-2 element. The results of DNA-protein binding experiments showed that RB increased nuclear binding activity to the RP-2 element, and site-directed mutation which disrupted binding of nuclear factors to the RP-2 element markedly reduced RB-mediated activation of Ren-1C promoter in human embryonic kidney cells. These results indicate that the RP-2 element plays an important role in RB-mediated transcriptional regulation of Ren-1C promoter activity in human embryonic kidney cells, thereby suggesting an interesting mechanism by which RB may modulate the renin-angiotensin system.
Tamura
K
K
Second Department of Internal Medicine, Yokohama City University School of Medicine, Yokohama 236, Japan.
Umemura
S
S
Nyui
N
N
Yamaguchi
S
S
Ishigami
T
T
Hibi
K
K
Yabana
M
M
Kihara
M
M
Fukamizu
A
A
Murakami
K
K
Ishii
M
M
D051696:Activating Transcription Factors; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D001798:Blood Proteins / Q000378:metabolism; D002478:Cells, Cultured; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012083:Renin / Q000235:genetics*; D016160:Retinoblastoma Protein / Q000378:metabolism*; D016329:Sp1 Transcription Factor / Q000378:metabolism; D016385:TATA Box; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic
D051696:Activating Transcription Factors; D001798:Blood Proteins; D017362:Cyclic AMP Response Element-Binding Protein; D011993:Recombinant Fusion Proteins; D016160:Retinoblastoma Protein; D016329:Sp1 Transcription Factor; D014157:Transcription Factors; D015500:Chloramphenicol O-Acetyltransferase; D012083:Renin