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An internal ribosome entry site mediates the initiation of soluble guanylyl cyclase β2 mRNA translation
Author(s) -
VazquezPadron Roberto I.,
Pham Si M.,
Mateu Dania,
Khan Sheik,
Aitouche Abdelouahab
Publication year - 2008
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2008.06505.x
Subject(s) - internal ribosome entry site , luciferase , messenger rna , translation (biology) , untranslated region , soluble guanylyl cyclase , microbiology and biotechnology , translational regulation , five prime untranslated region , biology , ribosome , transfection , chemistry , rna , gene , receptor , biochemistry , guanylate cyclase
The soluble guanylyl cyclases (sGC), the receptor for nitric oxide, are heterodimers consisting of an α‐ and β‐subunit. This study aimed to investigate the translational mechanism of the sGC β2‐subunit. Two mRNA species for sGC β2 were isolated from human kidney. These transcripts had dissimilar 5′‐untranslated regions (5′‐UTRs). The most abundant sGC β2 mRNA showed numerous upstream open reading frames (ORFs) and stable secondary structures that inhibited in vivo and in vitro translation . To evaluate whether these 5′‐UTRs harbored an internal ribosome entry site (IRES) that allows translation by an alternative mechanism, we inserted these regions between the two luciferase genes of a bicistronic vector. Transfection of those genetic constructs into HeLa cells demonstrated that both sGC β2 leaders had IRES activity in a cell‐type dependent manner. Finally, the secondary structural model of the sGC β2 5′‐UTR predicts a Y‐type pseudoknot that characterizes the IRES of cellular mRNAs. In conclusion, our findings suggest that sGC β2 5′‐UTRs have IRES activity that may permit sGC β2 expression under conditions that are not optimal for scanning‐dependent translation.