Molecular cloning of Aspergillus fumigatus CgrA, the ortholog of a conserved fungal nucleolar protein

In this report we describe the cloning of cgrA, the Aspergillus fumigatus ortholog of the yeast nucleolar protein Cgr1p. The cgrA complementary DNA (cDNA) contains a single open reading frame that would encode a protein of 114 amino acids that has 42% sequence identity to yeast Cgr1p. Heterologous expression of a green fluorescent protein (GFP)-tagged A. fumigatus cgrA gene demonstrated that the CgrA protein could localize to the yeast nucleolus. Moreover, the cgrA cDNA complemented the growth deficiency caused by inducible depletion of intracellular Cgr1p levels in yeast. These results support an orthologous relationship between the CgrA and Cgr1 proteins, and open the way for future studies into the potential value of nucleolar proteins as antifungal targets.