Fig 4.

Lack of TbPPR9 selectively affects the level of the COX1 and COX2 mRNAs. Total RNA from the uninduced TbPPR9 cell line and total RNA from the TbPPR9 RNAi cell line induced for the indicated times were analyzed for the levels of 9S rRNA (A) and 12S rRNA (B), as well as for the levels of COX1 (C), COX2 (D), CYTB (E), preedited A6 (F), preedited RPS12 (PE) (G), and edited RPS12 (H) RNAs, using Northern hybridization (upper part of top panels). To normalize for loading differences, each filter was reprobed for the mRNA of the cytosolic tryptophanyl-tRNA synthetase (TrpRS1) (lower part of top panels). The graphs show a quantification of the signals shown on the corresponding Northern blots. The level of the RNAs in uninduced cells was set to 100%. All RNA levels were normalized by using cytosolic TrpRS. The experiments for COX1 and COX2 were done in triplicate, using data from three independently induced cell lines, and the standard errors are indicated. The same applies for the time points of 0, 4, 5, and 6 days for all the other RNAs. For each cell line, the growth phenotype was monitored in parallel. The gray bar indicates the time interval when the growth phenotype became apparent. E, edited; UE, unedited.