2024-03-28T14:54:20Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/1297112019-03-22T13:16:48Zcom_10261_72com_10261_6com_10261_41com_10261_1col_10261_451col_10261_420
Miras, Manuel
Querol-Audí, Jordi
Truniger, Verónica
Silva-Espiña, Cristina
Verdaguer, Núria
Aranda, Miguel A.
2016-03-03T12:41:22Z
2016-03-03T12:41:22Z
2014-10-07
XVII Congreso de la Sociedad Española de Fitopatología (2014)
http://hdl.handle.net/10261/129711
http://dx.doi.org/10.13039/501100003329
Cap-independent translation is frequent for viral RNAs, which are often devoid of 5¿-cap structure or/and 3¿-poly(A) tail typical of eukaryotic mRNAs. Instead, many plant RNA viruses contain in their 3¿-UTRs RNA elements able to enhance their cap-independent translation (3¿-CITEs). It has been reported that 3¿-CITEs directly bind and require eukaryotic translation initiation factors (eIF) for their function. We have shown that cap-independent translation of Melon necrotic spot virus (MNSV) RNAs is controlled by a 3¿-CITE in cis (Truniger et al., 2008. Plant J. 56:716-727). Remarkably, MNSV 3¿-CITEs are diverse, including at least M¿5TE, M264TE and CXTE (Truniger et al., 2008; Miras et al., 2014. New Phytol. 202:233-246). Genetic evidence indicates that the eIF4E subunit of melon eIF4F is necessary for cap-independent translation of MNSV RNAs harboring M¿5TE (Nieto et al., 2006. Plant J. 48:452-462); in contrast, M264TE and CXTE are both eIF4E independent, conferring in cis translational competence to RNAs in the absence of this factor (Miras et al., 2014). On the one hand, we have performed in this study a structural and functional analysis of M¿5TE. Thus, we defined the minimal size of the 3¿-CITE in ¿in vivo¿ translation assays to a sequence of 45 nucleotides. Its secondary structure in solution was studied by Selective 2¿-Hydroxyl Acylation analyzed by Primer Extension (SHAPE) and compared with those of the other two types of 3¿-CITEs. On the other hand, we have expressed, crystalized and determined by X-ray crystallography the 3D structure of melon eIF4E. To describe the role of eIF4E in cap-independent translation of MNSV RNAs we are studying the M¿5TE:eIF4F interaction by several methods. Footprinting experiments revealed binding sites on a bulge of M¿5TE. Further structural and functional analyses, including co-crystallization of M¿5TE:eIF4F, are in progress.
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Structural analysis of a RNA viral element and its translation initiation factor partner, both controlling cap-independent translation of viral RNAs
póster de congreso