Possible role of c-Jun in transcription of the mouse renin gene.
BACKGROUND
Renin is a rate-limiting enzyme for activity of the circulating renin-angiotensin system (RAS) and expression of the renin gene is regulated by a variety of stimuli. In this study, we examined a possible role of c-Jun in the transcription of renin gene.


METHODS
The renin promoter, chloramphenicol acetyltransferase (CAT), fusion genes with or without c-Jun expression vector (pSV-c-Jun) were transfected into human embryonic kidney (HEK) cells, and the effects of c-Jun were examined by deletion and mutation analyses of CAT assay and by in vitro transcription-primer extension assay. We also examined the effects of c-Jun on DNA-binding activity to the renin promoter by electrophoretic mobility shift assay (EMSA). Furthermore, we examined the effects of c-Jun on transcription of the renin gene in enriched juxtaglomerular (JG) cells by cotransfection with pSV-c-Jun and by treatment with antisense c-jun oligodeoxynucleotides.


RESULTS
Promoter activity of the renin gene was increased by c-Jun overexpression in HEK cells, and the proximal promoter region from -47 to +16 was sufficient for transcriptional activation by c-Jun. Although mutation of activator protein-1 (AP-1) element-like sequences in the proximal promoter did not affect c-Jun-mediated stimulation, mutation of the core promoter including the TATA box inhibited c-Jun-mediated transcription. The results of EMSA showed that c-Jun overexpression produced a binding of nuclear factor, which was HEK cell-specific and distinct from TATA box-binding protein and AP-1 family transcription factor, to the renin core promoter region (RC element) from -36 to -20. The overexpression of c-Jun activated the renin promoter in renin-expressing JG cells, and antisense c-jun decreased the activity of renin promoter and expression of renin mRNA in JG cells.


CONCLUSIONS
These results indicate that the RC element plays a role in c-Jun-mediated transcriptional regulation of the renin gene in HEK cells, and suggest that c-Jun participates in the regulation of renin gene expression in JG cells of the kidney.
Department of Internal Medicine II, Yokohama City University School of Medicine, Japan. tamukou@yellow.med.yokohama-cu.ac.jp
K
K
Tamura
S
S
Umemura
N
N
Nyui
M
M
Yabana
Y
Y
Toya
A
A
Fukamizu
K
K
Murakami
M
M
Ishii
D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000378:metabolism; D006801:Humans; D007606:Juxtaglomerular Apparatus / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009154:Mutation; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D016755:Proto-Oncogene Proteins c-jun / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis; D012083:Renin / Q000235:genetics*; D014158:Transcription, Genetic
D016376:Oligonucleotides, Antisense; D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D004247:DNA; D012083:Renin