Abstract
In the absence of efficient transcription termination correct 3'-end processing is an essential step in the synthesis of stable chloroplast mRNAs in higher plants. We show here that 3'-end processing in vitro involves endonucleolytic cleavage downstream from the mature terminus, followed by exonucleolytic processing to a stem-loop within the 3'-untranslated region. These processing steps require a high molecular weight complex that contains both endoribonucleases and an exoribonuclease. In the presence of ancillary RNA binding proteins the complex correctly processes the 3'-end of precursor RNA. In the absence of these ancillary proteins 3'-end maturation is prevented and plastid mRNAs are degraded. Based on these results we propose a novel mechanism for the regulation of mRNA 3'-end processing and stability in chloroplasts.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Amino Acid Sequence
-
Chloroplasts / metabolism*
-
Cytochrome b Group / genetics
-
Cytochrome b6f Complex*
-
Endoribonucleases / metabolism
-
Molecular Sequence Data
-
Molecular Weight
-
Plant Proteins / metabolism*
-
Plastids / metabolism
-
Polyribonucleotide Nucleotidyltransferase / genetics
-
Polyribonucleotide Nucleotidyltransferase / metabolism
-
RNA Processing, Post-Transcriptional
-
RNA, Messenger / metabolism*
-
RNA, Plant / metabolism*
-
RNA-Binding Proteins / metabolism*
-
Ribonucleoproteins / chemistry
-
Ribonucleoproteins / genetics
-
Ribonucleoproteins / metabolism
-
Sequence Homology, Amino Acid
-
Spinacia oleracea / genetics
-
Spinacia oleracea / metabolism
Substances
-
Cytochrome b Group
-
Plant Proteins
-
RNA, Messenger
-
RNA, Plant
-
RNA-Binding Proteins
-
Ribonucleoproteins
-
petD protein, cytochrome b(6)f complex
-
Cytochrome b6f Complex
-
Polyribonucleotide Nucleotidyltransferase
-
Endoribonucleases