A nuclear-encoded function essential for translation of the chloroplast psaB mRNA in chlamydomonas.

摘要: We report the analysis of a photosystem I-deficient mutant Chlamydomonas reinhardtii, F15, that contains mutation at TAB1 (for translation psaB mRNA) nuclear locus. Pulse labeling chloroplast proteins revealed synthesis two I reaction center polypeptides PSAA and PSAB was undetectable in this mutant. The mRNA levels these were only moderately reduced, suggesting primary defect occurs step during or after translation. constructed chimeric genes consisting psaA 5' untranslated region (5' UTR) fused to aminoglycoside adenyltransferase (aadA) coding sequence, which confers spectinomycin resistance. Insertion into genome through biolistic transformation their expression background (but not psaA) UTR is target wild-type function. This suggests required for initiation dependence accumulation on strongly suggested by identification suppressor within UTR. specifically restores both presence tab1-F15 mutation. location putative base-paired near codon role activation mRNA.