The Saccharomyces cerevisiae response to zinc deficiency involves an MSN2/4 transcriptional response and G1 cell cycle arrest

Zinc is an essential element needed by all living cells. Its important role within cells is to stabilize proteins, act as a catalytic co-factor for enzymes and also involved in cell wall stabilization. Zinc deficiency is of big concern for the brewing industry and human health. A diet low in zinc can lead to impaired wound healing and immune function, hypogeusia, mental depression, anaemia and diarrhea. Wort lacking in zinc has implications on the fermentation process carried out by the yeast. Under zinc limiting conditions a large number of genes have been shown to be regulated by Zap1p. However, many other genes were differentially regulated by another unknown transcription factor. Interrogation of promoter sequences of these genes identified another consensus sequence 5' AGGGG 3' that was overrepresented. This motif is known to be the Stress Responsive Element (STRE) that the Msn2p/Msn4p complex binds. A microarray analysis of an msn2,msn4 mutant supported the role of this complex in the response to zinc-limiting conditions. It was also found that cells under zinc limitation conditions arrested in G1 phase of thecell cycle which the Msn2p/Msn4p complex has been implicated previously. These redundant transcription factors are known to be activated under a range of stress inducing environments and an investigation is under way to determine the molecular mechanisms involved in the activation of Msn2p/Msn4p in zinc-limiting conditions