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Annexin A2 and PSF proteins interact with p53 IRES and regulate translation of p53 mRNA

Sharathchandra, Arandkar and Lal, Ridhima and Khan, Debjit and Das, Saumitra (2013) Annexin A2 and PSF proteins interact with p53 IRES and regulate translation of p53 mRNA. In: RNA BIOLOGY, 9 (12). pp. 1429-1439.

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Official URL: http://dx.doi.org/10.4161/rna.22707

Abstract

p53 mRNA has been shown to be translated into two isoforms, full-length p53 (FL-p53) and a truncated isoform Delta N-p53, which modulates the functions of FL-p53 and also has independent functions. Previously, we have shown that translation of p53 and Delta N-p53 can be initiated at Internal Ribosome Entry Sites (IRES). These two IRESs were shown to regulate the translation of p53 and Delta N-p53 in a distinct cell-cycle phase-dependent manner. Earlier observations from our laboratory also suggest that the structural integrity of the p53 RNA is critical for IRES function and is compromised by mutations that affect the structure as well as RNA protein interactions. In the current study, using RNA affinity approach we have identified Annexin A2 and PTB associated Splicing Factor (PSF/SFPQ) as novel ITAFs for p53 IRESs. We have showed that the purified Annexin A2 and PSF proteins specifically bind to p53 IRES elements. Interestingly, in the presence of calcium ions Annexin A2 showed increased binding with p53 IRES. Immunopulldown experiments suggest that these two proteins associate with p53 mRNA ex vivo as well. Partial knockdown of Annexin A2 and PSF showed decrease in p53 IRES activity and reduced levels of both the p53 isoforms. More importantly the interplay between Annexin A2, PSF and PTB proteins for binding to p53mRNA appears to play a crucial role in IRES function. Taken together, our observations suggest pivotal role of two new trans-acting factors in regulating the p53-IRES function, which in turn influences the synthesis of p53 isoforms.

Item Type: Journal Article
Additional Information: Copyright for this article belongs to LANDES BIOSCIENCE, USA
Keywords: p53mRNA;IRES;IRES trans-acting factors;internal initiation of translation Annexin A2;PSF
Department/Centre: Division of Biological Sciences > Microbiology & Cell Biology
Depositing User: Francis Jayakanth
Date Deposited: 22 Mar 2013 12:14
Last Modified: 22 Mar 2013 12:14
URI: http://eprints.iisc.ac.in/id/eprint/46180

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