Work

Mechanism of RNA stabilization and translational activation by a pentatricopeptide repeat protein

Year: 2010

Type: article

Abstract: Pentatricopeptide repeat (PPR) proteins comprise a large family of helical repeat proteins that bind RNA and modulate organellar RNA metabolism. The mechanisms underlying the functions attributed to PPR proteins are unknown. We describe in vitro studies of the maize protein PPR10 that clarify how PPR10 modulates the stability and translation of specific chloroplast mRNAs. We show that recombinant PPR10 bound to its native binding site in the chloroplast atpI-atpH intergenic region (i) blocks both 5'→3' and 3'→ 5 exoribonucleases in vitro; (ii) is sufficient to define the native processed atpH mRNA 5'-terminus in conjunction with a generic 5'→3' exoribonuclease; and (iii) remodels the structure of the atpH ribosome-binding site in a manner that can account for PPR10's ability to enhance atpH translation. In addition, we show that the minimal PPR10-binding site spans 17 nt. We propose that the site-specific barrier and RNA remodeling activities of PPR10 are a consequence of its unusually long, high-affinity interface with single-stranded RNA, that this interface provides a functional mimic to bacterial small RNAs, and that analogous activities underlie many of the biological functions that have been attributed to PPR proteins.

Source: Proceedings of the National Academy of Sciences

DOI: 10.1073/pnas.1012076108

Authors: Jana Prikryl, Margarita Rojas, Gadi Schuster, Alice Barkan

Institutions: University of Oregon, Technion – Israel Institute of Technology

Language: English

Topic: Photosynthetic Processes and Mechanisms

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: green

Funder: National Science Foundation

Award: EAGER: Exploring the potential of pentatricopeptide repeat proteins for the site-directed modulation of RNA metabolism