Translation of the chloroplast psbA mRNA requires the nuclear-encoded poly(A)-binding protein, RB47.
A set of nuclear mutants of C. reinhardtii were identified that specifically lack translation of the chloroplast-encoded psbA mRNA, which encodes the photosystem II reaction center polypeptide D1. Two of these mutants are deficient in the 47-kD member (RB47) of the psbA RNA-binding complex, which has previously been identified both genetically and biochemically as a putative translational activator of the chloroplast psbA mRNA. RB47 is a member of the poly(A)-binding protein family, and binds with high affinity and specificity to the 5' untranslated region of the psbA mRNA. The results presented here confirm RB47's role as a message-specific translational activator in the chloroplast, and bring together genetic and biochemical data to form a cohesive model for light- activated translational regulation in the chloroplast.
Department of Cell Biology, and The Skaggs Institute of Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
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CB
Yohn
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A
Cohen
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C
Rosch
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MR
Kuchka
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Mayfield
D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D016825:Chlamydomonas reinhardtii / Q000235:genetics* / Q000378:metabolism* / Q000528:radiation effects; D002736:Chloroplasts / Q000378:metabolism / Q000528:radiation effects; D015870:Gene Expression; D008027:Light; D008954:Models, Biological; D016254:Mutagenesis, Insertional; D009154:Mutation; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics*; D045332:Photosystem II Protein Complex; D039102:Poly(A)-Binding Proteins; D014176:Protein Biosynthesis; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D016053:RNA, Protozoan / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*
D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D039102:Poly(A)-Binding Proteins; D015800:Protozoan Proteins; D012333:RNA, Messenger; D016053:RNA, Protozoan; D016601:RNA-Binding Proteins