The mitochondrial genotype can influence nuclear gene expression in yeast

Area of Science:

• Molecular biology
• Genetics
• Yeast research

Background:

• Respiratory-deficient yeast strains (e.g., mit-, petite) exhibit identical phenotypes despite varying mitochondrial genomes.
• Understanding the interplay between nuclear and mitochondrial genomes is crucial for cellular function.

Purpose of the Study:

• To investigate how yeast cells regulate nuclear gene expression in response to different mitochondrial DNA states.
• To identify nuclear-encoded transcripts affected by mitochondrial genome variations.

Main Methods:

• Subtractive hybridization of complementary DNA (cDNA) to polyadenylated RNA from derepressed yeast cultures.
• Analysis of transcript abundance in respiratory-deficient strains and their respiratory-competent parent.

Main Results:

• Nuclear-encoded transcripts showed varied abundance among respiratory-deficient strains and compared to the parent strain.
• Abundance of transcripts for certain mitochondrial proteins (cytochrome c, ATPase subunits) remained stable, unaffected by glucose or heme.
• Yeast cells modulate nuclear-encoded RNA levels in response to mitochondrial DNA quality and quantity.

Conclusions:

• Yeast cells exhibit a regulatory mechanism responding to mitochondrial DNA status.
• This suggests a form of intergenomic regulation, where nuclear gene expression is modulated by the mitochondrial genome.