Expression of the yeast calcineurin subunits CNA1 and CNA2 during growth and hyper-osmotic stress

CNA1 and CNA2 encode isoforms of the catalytic subunit of calcineurin, a Ser/Thr-specific phosphoprotein phosphatase regulated by Ca2+/calmodulin. The relative abundance of both transcripts was evaluated during growth of Saccharomyces cerevisiae in glucose by reverse-transcription polymerase chain reaction using PDA1 mRNA as a novel internal standard. CNA1 and CNA2 were concomitantly transcribed with different average expression ratios at the exponential and stationary growth phases and both showed a remarkable drop in the expression at diauxie. Prolonged hyper-osmotic shock resulted in a moderate induction of CNA1, whereas CNA2 expression was not affected. (C) 2003 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.