An interaction between two RNA binding proteins, Nab2 and Pub1, links mRNA processing/export and mRNA stability
Luciano H Apponi1, Seth M Kelly, Michelle T Harreman
1Department of Biological Sciences, School of Pharmaceutical Sciences, São Paulo State University, UNESP, Araraquara, SP 14801-902, Brazil.
Molecular and Cellular Biology
|July 20, 2007
Summary
Nuclear poly(A) binding protein 2 (Nab2) interacts with cytoplasmic Poly(U) binding protein 1 (Pub1) to regulate mRNA stability. This interaction is crucial for stabilizing specific transcripts containing AU-rich elements (AREs).
Area of Science:
- Molecular Biology
- RNA Biology
- Gene Regulation
Background:
- mRNA stability is regulated by RNA-binding proteins and transcript elements.
- Poly(U) binding protein 1 (Pub1) stabilizes cytoplasmic transcripts with AU-rich elements (AREs) or stabilizer elements (STEs).
- Nuclear poly(A) binding protein 2 (Nab2) is an essential protein involved in mRNA processing and export.
Purpose of the Study:
- To investigate the interaction between cytoplasmic Pub1 and nuclear Nab2.
- To determine the functional consequences of Nab2-Pub1 interaction on mRNA stability.
- To elucidate the role of Nab2 in modulating transcript turnover.
Main Methods:
- Yeast two-hybrid screening to identify interacting proteins.
- Copurification and in vitro binding assays to confirm protein interactions.
- Analysis of mRNA half-life in yeast mutants (nab2-1, nab2-67) using quantitative methods.
Main Results:
- Nab2 directly interacts with Pub1, mediated by Nab2's zinc finger domain.
- Nab2 modulates the stability of specific mRNA transcripts, similar to Pub1.
- The RPS16B transcript, containing an ARE-like sequence, shows decreased half-life in nab2 mutants, indicating Nab2-mediated stabilization.
- Nab2's stabilization effect on ARE-containing transcripts requires the ARE-like sequence.
Conclusions:
- Nab2 functions with Pub1 to regulate mRNA stability, particularly for ARE-containing transcripts.
- This study supports a model coupling nuclear events with cytoplasmic mRNA turnover.
- Nab2 plays a role in controlling mRNA stability beyond its known functions in mRNA processing and export.
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