Dual regulatory mechanisms of YGP1 expression in response to glucose availability in Saccharomyces cerevisiae
Cells adapt to fluctuating nutrient conditions by dynamically regulating gene expression, ensuring survival under stress. Ygp1, a secretory yeast glycoprotein, is one such gene that is induced by nutrition deprivation, particularly glucose starvation. In this study, we investigated the regulatory mechanisms underlying nutrition-deprivation-responsive changes in gene expression, focusing on YGP1 expression. Under glucose-rich conditions, YGP1 expression was positively regulated by the RNA-binding protein Puf5, a member of the Puf family. This regulation ensured rhythmic YGP1 expression during M phase of the cell cycle. The Puf5-mediated control targeted a specific 60-nucleotide region in the YGP1 promoter (−600 to −540 from the start codon), and this regulation was partly mediated by the acid stress-responsive transcriptional activator Haa1. In addition, upon glucose exhaustion (diauxic shift), YGP1 expression was strongly induced by the stress-responsive transcription factors Msn2 and Msn4 through the stress-response elements in the YGP1 promoter. Further analysis of the physiological significance of YGP1 expression revealed that the Puf5-mediated regulation contributes to the acid stress responses, and YGP1 expression supports cell survival in the puf5Δ background. In summary, YGP1 expression is regulated by two distinct factors in a glucose availability-dependent manner: Puf5 under glucose-rich conditions and the Msn2/Msn4 during glucose starvation. Especially, Puf5-mediated regulation contributes to the acid stress responses and subsequently supports long-term cell survival.