Title Functional Characterization of the Copper-Transporting P-Type ATPase Gene of Penicillium janthinellum Strain GXCR
Author Hongmin Lai1,2,3, Changbin Sun1,2,3, Huaying Tang1,2,3, Xianwei Fan1,2,3, and Yili Ma1,2,3*
Address 1Guangxi Key Laboratory of Subtropical Bioresource Conservation and Utilization, 2College of Life Science and Technology, 3Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, Guangxi University, Nanning, Guangxi 530005, P. R. China
Bibliography Journal of Microbiology, 47(6),736-745, 2009,
Key Words Penicillium, P-type ATPase, PcpA gene, resistance, heavy metal
Abstract Copper (Cu)-transporting P-type ATPase (CTPA) genes have been documented to play an important role in resistance to heavy metals. However, our understanding of roles of CTPA genes of the filamentous fungi was based only on sequence similarity prediction before. In a previous study, we isolated a Penicillum janthinellum strain GXCR of higher tolerance to Cu (200 mM). In this study, we cloned the partial cDNA of CTPA gene, named PcpA, from the strain GXCR. Sequence alignment indicated that the cloned cDNA sequence has the highest identity (94.4%) with a predictive CTPA gene of Aspergillus clavatus. The PcpA- encoded protein, termed PcpA, has classical functional domains of CTPAs, and shows differences from reported CTPAs in some specific sequence motifs and transmembrane regions. Expression of the PcpA was induced by extracellular Cu, cadmium (Cd), and silver (Ag). PcpA RNA interference (RNAi) mutants with a reduced level of PcpA mRNA were more sensitive to Cu, iron, Cd, and Ag than the wild-type (WT) strain GXCR. When grown in the presence of Cu, iron, and Cd, intracellular Cu and iron contents in the PcpA RNAi mutant were significantly (P<0.05) lower than those in the WT; However, intracellular Cd content in the mutant was significantly (P<0.05) higher than that in the WT. Taken together, it can be concluded that the PcpA functions in Cu uptake and homeostasis, iron uptake, and Cd export from the cytosol to the extracytosol.