Regulation of the AEFG1 gene, a mitochondrial elongation factor G from thedimorphic yeast Arxula adeninivorans LS3

Oxygen influences the synthesis of mitochondrial proteins by alteration of the expression of mitochondrial genes and several nuclear genes. One of the genes localised in the nucleus is the EFG1 gene that encodes the mitochond rial elongation factor G (MEF-G). This unique gene (AEFG1) has been isolate d from the non-conventional dimorphic yeast, Arxula adeninivorans LS3. The AEFG1 gene comprises a ORF of 2.274 bp, which corresponds to 757 amino acid s. In the present study, the regulation of AEFG1 has been analysed for diff erent morphological stages of A. adeninivorans and various culture conditio ns. It was demonstrated that the transfer of aerobically growing cultures t o anaerobic conditions resulted in an accumulation of AEFG1 transcript, cor relating with an increase in AMEF-G protein concentration. Since this regul ation occurred in budding-cell culture growing at 30 degreesC and in both o f the mycelial cultures grown at 45 degreesC and 30 degreesC, respectively, it was the oxygen level (but not the cultivation temperature or the morpho logical stage) which influenced the AEFG1 regulation.