Figure 5.

Chloroplast gene expression in pdm4 relative to the wild type. (A) The expression levels of plastid-encoded polymerase (PEP)-dependent chloroplast genes. (B) The expression levels of nuclear-encoded polymerase (NEP)-dependent chloroplast genes. (C) The expression levels of both PEP- and NEP-dependent chloroplast genes. The asterisks indicate significant differences between WT and pdm4 (Student’s t test; *p < 0.05; **p < 0.01; ***p < 0.001). (D) RNA gel-blot hybridization analysis of transcript levels for the different chloroplast gene classes. 5 μg of total RNA from 3-week old plants was size fractionated by agarose gel electrophoresis, transferred to a nylon membrane, and probed with ³²P-labeled cDNA probes for psaA, psbA, psbB, rbcL, rpoA, rpoB, and 18S rRNA. (E) RpoB protein content was indicated by western blot. Total protein (50 μg or the indicated dilution of the wild-type sample) from 3-week-old seedlings was loaded per lane. Actin was used as a loading control. These experiments obtained similar results each time. Results from a representative experiment of three times are shown.