Regulation of the AEFG1 gene, a mitochondrial elongation factor G from the dimorphic 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 mitochondrial elongation factor G (MEF-G). This unique gene (AEFG1) has been isolated from the non-conventional dimorphic yeast, Arxula adeninivorans LS3. The AEFG1 gene comprises a ORF of 2,274 bp, which corresponds to 757 amino acids. In the present study, the regulation of AEFG1 has been analysed for different morphological stages of A. adeninivorans and various culture conditions. It was demonstrated that the transfer of aerobically growing cultures to anaerobic conditions resulted in an accumulation of AEFG1 transcript, correlating with an increase in AMEF-G protein concentration. Since this regulation occurred in budding-cell culture growing at 30 degrees C and in both of the mycelial cultures grown at 45 degrees C and 30 degrees C, respectively, it was the oxygen level (but not the cultivation temperature or the morphological stage) which influenced the AEFG1 regulation.