Borah, S. and Shivarathri, R. and Srivastava, V. (2014) Pivotal Role for a Tail Subunit of the RNA Polymerase II Mediator Complex CgMed2 in Azole Tolerance and Adherence in Candida glabrata. Biochemical Journal, 463 (Part 1). pp. 103-114.

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Abstract

Antifungal therapy failure can be associated with increased resistance to the employed antifungal agents. Candida glabrata, the second most common cause of invasive candidiasis, is intrinsically less susceptible to the azole class of antifungals and accounts for 15% of all Candida bloodstream infections. Here, we show that C. glabrata MED2 (CgMED2), which codes for a tail subunit of the RNA polymerase II Mediator complex, is required for resistance to azole antifungal drugs in C. glabrata. An inability to transcriptionally activate genes encoding a zinc finger transcriptional factor, CgPdr1, and multidrug efflux pump, CgCdr1, primarily contributes to the elevated susceptibility of the Cgmed2 Delta mutant toward azole antifungals. We also report for the first time that the Cgmed2 Delta mutant exhibits sensitivity to caspofungin, a constitutively activated protein kinase C-mediated cell wall integrity pathway, and elevated adherence to epithelial cells. The increased adherence of the Cgmed2 Delta mutant was attributed to the elevated expression of the EPA1 and EPA7 genes. Further, our data demonstrate that CgMED2 is required for intracellular proliferation in human macrophages and modulates survival in a murine model of disseminated candidiasis. Lastly, we show an essential requirement for CgMed2, along with the Mediator middle subunit CgNut1 and the Mediator cyclin-dependent kinase/cyclin subunit CgSrb8, for the high-level fluconazole resistance conferred by the hyperactive allele of CgPdr1. Together, our findings underscore a pivotal role for CgMed2 in basal tolerance and acquired resistance to azole antifungals.

Item Type:	Article
Uncontrolled Keywords:	adherence; Candida glabrata; common in fungal extracellular membranes (CFEM) domain; haemolysin; high-affinity iron uptake; intracellular iron content; virulence
Subjects:	Molecular Biology
Depositing User:	Unnamed user with email alok@urdip.res.in
Date Deposited:	11 Feb 2015 05:13
Last Modified:	11 Feb 2015 05:13
URI:	http://dst.sciencecentral.in/id/eprint/9

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