Target and specificity of a nuclear gene product that participates in mRNA 3'-end formation in Chlamydomonas chloroplasts.
Chloroplast mRNA maturation is catalyzed by nucleus-encoded processing enzymes. We previously described a recessive nuclear mutation (crp3) that affects 3'-end formation of several chloroplast mRNAs in Chlamydomonas reinhardtii (Levy, H., Kindle, K. L., and Stern, D. B. (1997) Plant Cell 9, 825-836). In the crp3 background, atpB mRNA lacking a 3'-inverted repeat normally required for stability accumulates as a discrete transcript. The mutation also affects the atpA gene cluster; polycistronic mRNAs with psbI or cemA 3'-ends accumulate to a lower level in the crp3 background. Here, we demonstrate that the crp3 mutation also alters 3'-end formation of psbI mRNA and cemA-containing mRNAs. A novel 3'-end is formed in monocistronic psbI transcripts, and this is the only terminus observed when the psbI 3'-untranslated region is fused to an aadA reporter gene. Accumulation of mRNAs with 3'-ends between cemA and atpH, which is immediately downstream, was reduced. However, this sequence was not recognized as a 3'-end formation element in chimeric genes. The crp3 mutation was able to confer stability to three different atpB 3'-stem-loop-disrupting mutations that lack sequence similarity, but are located at a similar distance from the translation termination codon. We propose that the wild-type CRP3 gene product is part of the general 3' --> 5' processing machinery.
Levy
H
H
Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, New York 14853-1801, USA.
Kindle
K L
KL
Stern
D B
DB
D020413:3' Untranslated Regions / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D016825:Chlamydomonas reinhardtii / Q000235:genetics* / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism*; D017343:Genes, Plant; D005808:Genes, Recessive; D005810:Multigene Family; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D012091:Repetitive Sequences, Nucleic Acid; D017384:Sequence Deletion; D014158:Transcription, Genetic
D020413:3' Untranslated Regions; D012333:RNA, Messenger