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Functional analysis of the Arabidopsis thaliana CHLOROPLAST BIOGENESIS 19 pentatricopeptide repeat editing protein
Author(s) -
RamosVega Maricela,
GuevaraGarcía Arturo,
Llamas Ernesto,
SánchezLeón Nidia,
OlmedoMonfil Vianey,
VielleCalzada Jean Philippe,
León Patricia
Publication year - 2015
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.13468
Subject(s) - pentatricopeptide repeat , biogenesis , arabidopsis thaliana , chloroplast , biology , arabidopsis , microbiology and biotechnology , botany , genetics , computational biology , gene , mutant
Summary The Arabidopsis thaliana pentatricopeptide repeat ( PPR ) family of proteins contains several degenerate 35‐aa motifs named PPR repeats. These proteins control diverse post‐transcriptional regulatory mechanisms, including RNA editing. CLB 19 belongs to the PLS subfamily of PPR proteins and is essential for the editing and functionality of the subunit A of plastid‐encoded RNA polymerase (RpoA) and the catalytic subunit of the Clp protease (ClpP1). We demonstrate in vitro that CLB 19 has a specific interaction with these two targets, in spite of their modest sequence similarity. Using site‐directed mutagenesis of the rpoA target, we analyzed the essential nucleotides required for CLB 19– rpoA interactions. We verified that, similar to other editing proteins, the C‐terminal E domain of CLB 19 is essential for editing but not for RNA binding. Using biomolecular fluorescence complementation, we demonstrated that the E domain of CLB 19 interacts with the RNA ‐interacting protein MORF 2/ RIP 2 but not with MORF 9/ RIP 9. An interesting finding from this analysis was that overexpression of a truncated CLB 19 protein lacking the E domain interferes with cell fate during megasporogenesis and the subsequent establishment of a female gametophyte, supporting an important role of plastids in female gametogenesis. Together these analyses provide important clues about the particularities of the CLB 19 editing protein.