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Knockout of the plastid RNase E leads to defective RNA processing and chloroplast ribosome deficiency
Author(s) -
Walter Michael,
Piepenburg Katrin,
Schöttler Mark Aurel,
Petersen Kerstin,
Kahlau Sabine,
Tiller Nadine,
Drechsel Oliver,
Weingartner Magdalena,
Kudla Jörg,
Bock Ralph
Publication year - 2010
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2010.04377.x
Subject(s) - rnase p , biology , rnase mrp , rna , degradosome , plastid , ribosome , chloroplast , ribonuclease iii , ribosomal rna , gene , ribonuclease , gene expression , operon , genetics , microbiology and biotechnology , mutant , rna interference
Summary Ribonuclease E (RNase E) represents a key enzyme in bacterial RNA metabolism. It plays multifarious roles in RNA processing and also initiates degradation of mRNA by endonucleolytic cleavage. Plastids (chloroplasts) are derived from formerly free‐living bacteria and have largely retained eubacterial gene expression mechanisms. Here we report the functional characterization of a chloroplast RNase E that is encoded by a single‐copy nuclear gene in the model plant Arabidopsis thaliana . Analysis of knockout plants revealed that, unlike in bacteria, RNase E is not essential for survival. Absence of RNase E results in multiple defects in chloroplast RNA metabolism. Most importantly, polycistronic precursor transcripts overaccumulate in the knockout plants, while several mature monocistronic mRNAs are strongly reduced, suggesting an important function of RNase E in intercistronic processing of primary transcripts from chloroplast operons. We further show that disturbed maturation of a transcript encoding essential ribosomal proteins results in plastid ribosome deficiency and, therefore, provides a molecular explanation for the observed mutant phenotype.