Mutational analysis of the J-K stem-loop region of the encephalomyocarditis virus IRES.
AUTOR(ES)
Hoffman, M A
RESUMO
Cap-independent translation of encephalomyocarditis virus (EMCV) RNA is controlled by a segment of the 5' untranslated region termed the internal ribosomal entry site, or IRES. The IRES contains a series of stem-loop structural elements. The J and K stems (EMCV bases 682 to 795), near the center of the IRES, are well conserved among all cardio-, aphtho-, and hepatoviruses. We have examined the biological roles of these elements by constructing mutations within the J-K sequences of EMCV and testing the mutations for activity in translation, translation competition, UV cross-linking, and viral infectivity assays. Mutations near the helical junction of J and K proved severely detrimental to both cellular translation and cell-free translation of downstream cistrons. The same mutations reduced the ability of the IRES to compete for cellular factors in competition assays and reduced the infectivity of viral genomes carrying these lesions. A mutation in the terminal loop of J gave similar results. In contrast, mutations within the terminal loop of K had minimal impact on in vitro translation activity and IRES competitive ability. However, in vivo analysis of the K-loop mutations revealed deficiencies during cellular translation and further showed markedly reduced infectivity in HeLa cells. UV cross-linking experiments identified a 49-kDa protein which interacts strongly with the J-K region, but the identity of this protein and its contribution to IRES activity are unclear.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=189181Documentos Relacionados
- Revertant analysis of J-K mutations in the encephalomyocarditis virus internal ribosomal entry site detects an altered leader protein.
- Inhibition of hepatitis C virus IRES-mediated translation by small RNAs analogous to stem–loop structures of the 5′-untranslated region
- RNA Destabilization by the Granulocyte Colony-Stimulating Factor Stem-Loop Destabilizing Element Involves a Single Stem-Loop That Promotes Deadenylation
- Analysis of Natural Variants of the Human Immunodeficiency Virus Type 1 gag-pol Frameshift Stem-Loop Structure
- Translation elongation factor-1 alpha interacts with the 3' stem-loop region of West Nile virus genomic RNA.