INVESTIGADORES
BELLORA nicolas
artículos
Título:
Structural basis for the biological relevance of the invariant apical stem in IRES-mediated translation
Autor/es:
NOEMI FERNANDEZ; OLGA FERNANDEZ-MIRAGALL; JORGE RAMAJO; ANA GARCIA-SACRISTAN; NICOLAS BELLORA; EDUARDO EYRAS; CARLOS BRIONES; ENCARNACION MARTINEZ-SALAS
Revista:
NUCLEIC ACIDS RESEARCH
Editorial:
OXFORD UNIV PRESS
Referencias:
Lugar: Oxford; Año: 2011 vol. 39 p. 8572 - 8585
ISSN:
0305-1048
Resumen:
RNA structure plays a fundamental role in internal initiation of
translation. Picornavirus internal ribosome entry site (IRES) are long,
efficient cis-acting elements that recruit the ribosome to internal
mRNA sites. However, little is known about long-range constraints
determining the IRES RNA structure. Here, we sought to investigate the
functional and structural relevance of the invariant apical stem of a
picornavirus IRES. Mutation of this apical stem revealed better
performance of G:C compared with C:G base pairs, demonstrating that the
secondary structure solely is not sufficient for IRES function. In
turn, mutations designed to disrupt the stem abolished IRES activity.
Lack of tolerance to accept genetic variability in the apical stem was
supported by the presence of coupled covariations within the adjacent
stem-loops. SHAPE structural analysis, gel mobility-shift and
microarrays-based RNA accessibility revealed that the apical stem
contributes to maintain IRES RNA structure through the generation of
distant interactions between two adjacent stem-loops. Our results
demonstrate that a highly interactive structure constrained by distant
interactions involving invariant G:C base pairs plays a key role in
maintaining the RNA conformation necessary for IRES-mediated
translation.