Comparative analysis of transcripts from mia40-4int mutant and wild-type Saccharomyces cerevisiae strains quantified in RNA-seq experiment

The vast majority of the mitochondrial proteome originates from nuclear genes and is transported into the organelle after synthesis in the cytosol. Complex machineries, which maintain the specificity of protein import and sorting exist. Dysfunctions of mitochondrial protein sorting pathways result in diminishing specific substrate proteins, followed by systemic pathology of the organelle and organismal death. Cellular responses that are caused by slowdown in the transport of mitochondrial proteins are unknown. Here we have used RNA-seq transcription profiling of Saccharomyces cerevisiae to uncover the changes in the cellular transcriptome in the response to mitochondrial protein import dysfunction caused by mutation in the MIA40 gene. Mia40 is a key component of the mitochondrial intermembrane import and assembly (MIA) pathway. Mia40-4int mutant used in this study is not viable at high temperatures, while in the low, permissive temperature it expresses growth rate comparable to the wild-type strain. Even during the permissive temperature culture mutant cells are characterized by decreased accumulation of MIA substrate proteins. Thus permissive growth conditions were used in the present experiment to emphasise primary responses to mitochondrial protein import defect.

6