Figure 6.—

Effect of the overexpression of RMD9 on the accumulation of mitochondrial transcripts. The wild-type (CW252) and the oxa1-E65G-F229S strains were transformed with the empty control vector pFL44L (−) and YepSU27 carrying RMD9 (RMD9). Total RNAs were isolated from the transformants grown in minimal medium to maintain the plasmids. (A) RNAs (2 μg) were analyzed by hybridization with probes specific for the nuclear gene RMD9, for the protein-encoding mitochondrial genes COX2 and ATP9, as well as for the mitochondrial rRNAs 21S and 15S (see materials and methods). (B) mRNA levels were quantified with ImageQuant (Molecular Dynamics, Sunnyvale, CA) and normalized to the levels of actin mRNA (ACT1). The histogram presents the steady-state level of three representative mitochondrial RNAs (ATP9, COX2, and 15S) in the strain overexpressing RMD9 as compared to their level in the strain transformed with the control vector.