Cloning and characterization of the gene encoding translation elongation factor 1 alpha from Aureobasidium pullulans

Abstract

The gene (TEF1) encoding translation elongation factor 1 alpha from the dimorphic fungus Aureobasidium pullulans (Ap) strain R106 has been cloned using Candida albicans TEF1 as a heterologous hybridization probe. Electrophoretic molecular karyotype/hybridization analysis of Ap revealed eight chromosomal bands and suggested that TEF1 resides on chromosome VI. Comparison of the genomic DNA sequence with the cDNA sequence of TEF1 verified the presence of three introns, the first one occurring five nucleotides from the start of translation. The deduced amino acid (aa) sequence encoded a protein consisting of 459 aa (49,663 Da) possessing high identity to a variety of TEF1-encoded proteins. A strong codon bias, similar to that observed in highly expressed yeast genes, was evident in A. pullulans TEF1. The ApTEF1 promoter region showed some sequence similarity to the well-studied TEF1 promoter from Saccharomyces cerevisiae, including a region from -23 to -11. This region exhibited high homology to a promoter upstream activating sequence (UAS) in S. cerevisiae. Such sequences have been shown to be essential promoter elements in genes coding for the highly expressed components of the yeast translation apparatus.