Biphasic zinc compartmentalisation in a human fungal pathogen
Fig 1
pH-dependent functionality and regulation of Zrt1 and Zrt2 in C. albicans.
(A) Zrt2 is essential in acidic medium. Indicated strains, precultured in YPD, were washed and cultured in SD (YNB+glucose) medium alone, or supplemented with 100 μM ZnSO4 or with 50 mM HEPES pH 7.4. Asterisks indicate statistical significance compared to the wild type; # indicates statistical significance compare to the zrt2Δ in SD; P <0.05. (B) ZRT1 promoter activity is pH regulated and ZRT2 is constitutively expressed under zinc limitation. (PZRT1-GFP and PZRT2-GFP reporter strains in LZM buffered to indicated pH values). LZM was used due to lower green autofluorescence. Experiment performed three times. (C) Double deletion of ZRT1 and ZRT2 precludes growth at both acidic and neutral alkaline pH. Strains were cultured as in (A) and growth kinetics measured over 48 h in a microtitre plate. Experiment performed twice in triplicate.