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Translation Inhibition of Vascular Endothelial Growth Factor mRNA by the GAIT Translational Silencing Complex
Author(s) -
Ray Partho Sarothi,
Fox Paul L.
Publication year - 2006
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.20.4.a537-c
Subject(s) - messenger rna , gene silencing , translation (biology) , untranslated region , au rich element , microbiology and biotechnology , biology , translational regulation , reporter gene , gene expression , eukaryotic translation , chemistry , gene , genetics
Delayed silencing of ceruloplasmin (Cp) mRNA translation in interferon (IFN)‐gamma‐activated monocytic cells is mediated by interaction of the multiprotein IFN‐Gamma‐Activated Inhibitor of Translation (GAIT) complex with a defined RNA stem‐loop (GAIT element) in the Cp mRNA 3′‐UTR. Coordinate, post‐transcriptional regulation of functionally related genes by RNA‐binding proteins has been shown for mRNAs containing common sequence/structural elements. To gain insight into the physiological role of GAIT‐mediated translation silencing, we investigated whether the complex regulated translation of other mRNAs. Application of a pattern‐searching algorithm to an mRNA 3′‐UTR database revealed multiple transcripts containing potential GAIT elements. Identification of vascular endothelial growth factor (VEGF) as a putative GAIT target was of particular interest since it is produced by inflammatory macrophages. Interaction of VEGF mRNA with the GAIT complex was shown by immunoprecipitation of the complex from U937 cell lysate, isolation of bound mRNAs, and RT‐PCR using VEGF‐specific primers. Translation of a reporter transcript ligated to the VEGF mRNA 3′‐UTR was silenced by IFN‐treated U937 cell lysate, indicating the presence of an authentic GAIT element. VEGF protein synthesis declined about 16 h after IFN treatment, despite the presence of VEGF mRNA, indicating the pathway is operative in vivo . This constitutes the first report of negative control of VEGF gene expression and suggests that the GAIT complex coordinately regulates the translation of a network of pro‐inflammatory genes. Research support: NIH grant PO1HL29582