title: Expression and functional characterisation of TNC, a high-affinity nickel transporter from Neurospora crassa.
abstract: Our previous in silico studies identified a high-affinity nickel transporter, TNC, from the metal transportome of Neurospora crassa. A knockout mutant of the tnc gene in N. crassa failed to transport nickel, showed phenotypic growth defects and diminished urease activity under physiological levels of nickel. Transport assays conducted in wild type and knockout mutant strains showed that TNC transports nickel with high affinity but exhibits selectivity for other transition metal ions like cobalt. Heterologous complementation of Schizosaccharomyces pombe nickel uptake mutant by TNC further substantiates its nickel transport function. Transcriptional analysis of the nickel transporter encoding gene, tnc in N. crassa by qRT-PCR showed its constitutive expression in various phases of its life cycle. However, levels of the corresponding protein TNC were down-regulated only by increasing the nickel, but not cobalt concentration in the media. Immunolocalisation data suggested that TNC is distributed in the plasma membrane of N. crassa. Thus, the present study establishes TNC as a functional plasma membrane nickel transporter necessary for physiological acquisition of nickel in the multicellular fungi N. crassa.
authors.affiliation: Department of Biochemistry, University College of Science, Osmania University, Hyderabad 500007, India.
authors.forename: Anand
authors.initials: A
authors.lastname: Tiwari
authors.forename: Premsagar
authors.initials: P
authors.lastname: Korripally
authors.forename: Haritha
authors.initials: H
authors.lastname: Adhikarla
authors.forename: Kiranmayi
authors.initials: K
authors.lastname: Patnala
authors.forename: Maruthi Mohan
authors.initials: MM
authors.lastname: Pamarthi
authors.forename: Manjula
authors.initials: M
authors.lastname: Bhanoori
mesh_terms: D002462:Cell Membrane / Q000737:chemistry; D003035:Cobalt / Q000378:metabolism; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D055786:Gene Knockout Techniques; D005816:Genetic Complementation Test; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D009492:Neurospora crassa / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D009532:Nickel / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D014510:Urease / Q000378:metabolism
chemical_list: D026901:Membrane Transport Proteins; D003035:Cobalt; D009532:Nickel; D014510:Urease