Function of plastid mRNA 3' inverted repeats. RNA stabilization and gene-specific protein binding.
Plastid protein coding regions in plants are generally flanked by 3' inverted repeat (IR) sequences. In a previous work (Stern, D. B., and Gruissem, W. (1987) Cell 51, 1145-1157), we have shown that their role may be in RNA stabilization and as a processing signal that establishes the mature mRNA 3' end. In this report we have investigated the stability and protein interaction of chloroplast mRNA 3' IR-RNA sequences in more detail. Progressive deletions into the 3' IR-RNA sequences for the chloroplast cytochrome b6/f subunit IV (petD) mRNA reduce the stability of the RNA, indicating that the potential to form a stem/loop is a minimum requirement for petD 3' IR-RNA stability in vitro. Specific point mutants also destabilize the processed 3' IR-RNA, suggesting an important role for the primary sequence. Gel mobility shift and UV-cross-linking analysis has shown that 3' IR-RNAs of petD and two other chloroplast mRNAs (rbcL and psbA) interact with proteins in vitro. Comparison of the bound petD 3' IR-RNA proteins with proteins that bind to rbcL and psbA reveals that binding of certain proteins is gene-specific. Also, precursor and processed petD 3' IR-RNAs bind different sets of proteins. A single nucleotide transversion (T----A) near the base of the stem eliminates the binding of a 29-kDa protein to the petD 3' IR-RNA precursor. We discuss the possible role of 3' IR-RNA-protein interactions in plastid mRNA 3' end maturation and differential mRNA stability.
Stern
D B
DB
Department of Plant Biology, University of California, Berkeley 94720.
Jones
H
H
Gruissem
W
W
D001483:Base Sequence; D001667:Binding, Competitive; D002352:Carrier Proteins / Q000378:metabolism*; D002736:Chloroplasts / Q000032:analysis*; D002845:Chromatography; D003573:Cytochrome b Group / Q000235:genetics*; D045346:Cytochrome b6f Complex; D004355:Drug Stability; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D010940:Plant Proteins / Q000378:metabolism*; D010944:Plants / Q000235:genetics*; D012313:RNA / Q000378:metabolism*; D012322:RNA Precursors / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics*; D016601:RNA-Binding Proteins; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*; D014466:Ultraviolet Rays
D002352:Carrier Proteins; D003573:Cytochrome b Group; D010940:Plant Proteins; D012322:RNA Precursors; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012313:RNA; D045346:Cytochrome b6f Complex