Protein expression and subcellular localization of the general purine transporter UapC from Aspergillus nidulans

The uapC gene of Aspergillus nidulans belongs to a family of nucleobase-spe cific transporters conserved in prokaryotic and eucaryotic organisms. We re port the use of immunological and green fluorescent protein based strategie s to study protein expression and subcellular distribution of UapC, A chime ric protein containing a plant-adapted green fluorescent protein (sGFP) fus ed to the C-terminus of UapC was shown to be functional in vivo, as it comp lements a triple mutant (i.e., uapC(-) uapA azgA(-)) unable to grow on uric acid as the sole nitrogen source, UapC-GFP is located in the plasma membra ne and, secondarily, in internal structures observed as fluorescent dots. A strong correlation was found between cellular levels of UapC-GFP fluoresce nce and known patterns of uapC gene expression. This work represents the fi rst in vivo study of protein expression and subcellular localization of a f ilamentous fungal nucleobase transporter, (C) 2000 Academic Press.