Linker scanning mutagenesis of the internal ribosome entry site of poliovirus RNA.

AUTOR(ES)

Haller, A A

RESUMO

The initiation of cap-independent translation of poliovirus mRNA occurs as a result of ribosome entry at an internal site(s) within the 5' noncoding region. A series of linker scanning mutations was constructed to define the genetic determinants of RNA-protein interactions that lead to high-fidelity translation of this unusual viral mRNA. The mutations are located within two distinct stem-loop structures in the 5' noncoding region of poliovirus RNA that constitute a major portion of a putative internal ribosome entry site. On the basis of our data derived from genetic and biochemical assays, the stability of one of the stem-loop structures appears to be essential for translation initiation via internal binding of ribosomes. However, the second stem-loop structure may function in a manner that requires base pairing and proper spacing between specific nucleotide sequences. By employing RNA electrophoretic mobility shift assays, an RNA-protein interaction was detected for this latter stem-loop structure that does not occur in RNAs containing mutations which perturb the predicted hairpin structure. Analysis of in vivo-selected virus revertants, in combination with mobility shift assays, suggests that extensive genetic rearrangement can lead to restoration of 5' noncoding region functions, possibly by the repositioning of specific RNA sequence or structure motifs.

Documentos Relacionados

• Internal ribosome entry site within hepatitis C virus RNA.
• Replication of Poliovirus RNA with Complete Internal Ribosome Entry Site Deletions
• Host range phenotype induced by mutations in the internal ribosomal entry site of poliovirus RNA.
• Minimum internal ribosome entry site required for poliovirus infectivity.
• Sequences within the poliovirus internal ribosome entry segment control viral RNA synthesis.