Fig. 1. Analysis of mitochondrial translation in nam1 and sls1 null mutant strains.

A, Northern analysis of mitochondrial transcripts. Mitochondrial RNA was extracted and prepared for Northern analysis as described (10). The strains analyzed have been described previously (9) and are indicated above the figure: CMW2 (wt) and CMW1 (sls1Δ). Signals for the mature mitochondrial RNA transcripts COB, COX1, and COX3 are indicated on the left. B, specific labeling of mitochondrial translation products in vivo. Shown is an autoradiogram of mtDNA-encoded proteins labeled with [³⁵S]methionine at 30 °C in the presence of cycloheximide as described under “Experimental Procedures.” The strains analyzed are the same as those described in A. C, overexpression of Sls1p restores in vivo labeling of mitochondrial proteins in an nam1Δ strain. Shown is an autoradiogram of mtDNA-encoded translation products labeled in cultures at 30 °C. The strains analyzed have been described previously (9) and are indicated at the top of each lane: GS140 (wt), GS141 (nam1Δ), and ACB1 (nam1Δ + pRS316-SLS1). The identity of each labeled mtDNA-encoded protein is indicated on the left of the figure in both B and C.