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A far upstream Oct‐1 motif regulates cytokine induction of human inducible nitric oxide synthase (hiNOS) gene
Author(s) -
Park Kyung Soo,
Guo Zhong,
Geller David
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a285-d
Subject(s) - promoter , electrophoretic mobility shift assay , chromatin immunoprecipitation , microbiology and biotechnology , transcription factor , gene silencing , sequence motif , biology , transcription (linguistics) , mutant , gene expression , gene , chemistry , genetics , linguistics , philosophy
Transcriptional regulation of hiNOS gene is highly complex and tightly controlled. It requires an orchestrated flow of positive and negative transcription factors that bind to specific cis‐acting upstream response elements. The hiNOS promoter is known to be one of the largest promoters with inducible elements extending up to −16 kb. Oct‐1 protein belongs to the POU domain transcription factor family and is constitutively expressed in all dividing cells. Therefore, it's essential for proliferation, differentiation and other key cell processes. Oct‐1 binding to DNA may either stimulate or inhibit transcription of the target gene. In this work, the octamer sequence ATGCAAAT at −10.2 kb of the hiNOS promoter was identified as high‐affinity Oct‐1 binding by electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assay. Cytokine‐induced hiNOS promoter activity was significantly reduced by Oct‐1 siRNA targeting. Mutation of the Oct‐1 motif decreased cytokine‐induced hiNOS promoter activity by 40 % and Oct‐1 silencing also reduced the promoter activity of mutant hiNOS at −10.2 Oct‐1. Taken together, we found a functional Oct‐1 motif regulating hiNOS gene expression at −10.2 kb in the hiNOS promoter.