Regulation of human inducible nitric oxide synthase expression by an upstream open reading frame.
Nitric Oxide
; 88: 50-60, 2019 07 01.
Article
in En
| MEDLINE
| ID: mdl-31004763
ABSTRACT
The human inducible nitric oxide synthase (iNOS) gene contains an upstream open reading frame (uORF) in its 5'-untranslated region (5'-UTR) implying a translational regulation of iNOS expression. Transfection experiments in human DLD-1â¯cells revealed that the uORF although translatable seems not to inhibit the translation start at the bona fide ATG. Our data clearly show that human iNOS translation is cap-dependent and that the 5'-UTR of the iNOS mRNA contains no internal ribosome entry site. Translation of the bona fide coding sequence is most likely mediated by a leaky scanning mechanism. The 5'-UTR is encoded by exon 1 and exon 2 of the iNOS gene with the uORF stop codon located in front of the first intron indicating an involvement of the nonsense mediated RNA decay (NMD) in iNOS regulation. SiRNA-mediated down-regulation of Upf1 resulted in enhanced endogenous cytokine iNOS expression in human DLD-1â¯cells. Transfection of constructs containing iNOS exon 1, intron 1 and exon 2 in front of a luciferase gene showed a clear effect of the mutation of the uORF-ATG on luciferase reportergene expression. Our data indicate that the uORF in the 5'-UTR sequence of human iNOS gene reduces its expression via the NMD mechanism.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Gene Expression Regulation
/
Open Reading Frames
/
Nitric Oxide Synthase Type II
Limits:
Humans
Language:
En
Journal:
Nitric Oxide
Year:
2019
Document type:
Article