Posttranscriptional accumulation of chloroplast tufA (elongation factor gene) mRNA during chloroplast development in Chlamydomonas reinhardtii.

Light induces chloroplast (Cp) differentiation in dark-grown y-1 strains of Chlamydomonas reinhardtii. Slot blot analysis was used to quantitate tufA, psbA, psbK, rbcL, and 16S rRNA transcript accumulation and transcription during Cp differentiation. When etiolated cc-125 y-1 cells were illuminated for 5 h, a 1710 bp tufA mRNA accumulated up to 5-fold while the psbA, rbcL, and 16S rRNA transcripts accumulated less than 1.5-fold. The tufA gene encodes translational elongation factor EF-Tu. The light-induced accumulation of tufA mRNA did not occur in cc-1931, a strain that does not become etiolated in darkness. Pulse labelling was used to measure the transcription of Cp transcripts during tufA mRNA accumulation, and no detectable change in tufA transcription was observed. These results imply that the half life of the tufA transcript increases during the greening process.