Multi-Copy Suppression of an Aspergillus nidulans Mutant Sensitive to Camptothecin by a Putative Monocarboxylate Transporter

Abstract

The Monocarboxylate Transporter (MCT) is a family of membrane proteins from the Major Facilitator Superfamily (MFS) of transporters. Here, we report the first identified Aspergillus nidulans MCT homologue, AmcA. The amcA gene was isolated by high copy number suppression of the hydroxyurea (HU) sensitivity of an A. nidulans camptothecin-sensitive mutant. Expression of amcA is increased when hyphae are grown in media containing acetate or pyruvate as single carbon source, and after exposure to several unrelated drugs. Our results suggest that AmcA could be involved not only in monocarboxylate transport, but also in drug secretion. To our knowledge, this is the first report suggesting a possible involvement of MCT transporters with drug resistance in eukaryotic cells.