FIGURE 6.

Growth is inhibited upon simultaneous down-regulation of MRB8170 and MRB4160 but persists when each is individually RNAi-silenced. (A) A bar graph on a linear scale showing the mean relative transcript abundance as determined by qRT-PCR in MRB8170/4160 double- and single-knockdown cell lines treated with the RNAi-induction agent tetracycline in comparison to those grown in the absence of the antibiotic. Data were normalized to cytosolic β-tubulin (black) and 18S rRNA (gray) levels. A value of 1 indicates no change, while a value <1 signifies depletion of the assayed transcript. The range of obtained relative abundances is signified by whiskers around the top of the bars. (B) Western analysis of resolved mitochondrial proteins from the studied cell lines was performed to assay the depletion of MRB8170 in kMAP double and single knockdowns. The mitochondrial protein trCoIV was used as a loading control. (C) The growth rate of cells grown in the presence (black diamond and line) or absence (gray square and line) of tetracycline for the MRB8170/4160 double and single knockdowns over a 14-d course. Cell density (cells/mL) was measured every 24 h, and the cells were diluted to the starting density of 2 × 10⁶ cells/mL every second day.