CLONING AND ANALYSIS OF CDNA-ENCODING AN ELONGATION-FACTOR 1-ALPHA FROM THE DIMORPHIC FUNGUS HISTOPLASMA-CAPSULATUM

The cDNA encoding translation elongation factor 1 alpha (EF-1 alpha) was isolated from the dimorphic fungus, Histoplasma capsulatum (Hc), an important pathogen of man. A cDNA library was probed with the tef1 gene from the fungus Mucor racemosus. Ten independent clones were isolated, all with similar restriction patterns. The longest clone (1.96 kb) was sequenced. Southern blot analysis revealed that the He tef1 gene was present as a single copy. A single transcript of approx. 2300 nucleotides was found in total RNA from both the yeast and mold forms of the organism. Comparison of the deduced 460-amino-acid He EF-1 alpha protein to EF-1 alpha proteins from other species of fungi revealed the greatest degree of similarity to proteins from the filamentous ascomycetes Podospora anserina and Trichoderma reesei. Phylogenetic tree analysis of fungal tef genes indicated that Hc is most closely related to filamentous ascomycetes and most distantly related to the budding yeast Saccharomyces cerevisiae.