PAP1 [poly(A) polymerase 1] homozygosity and hyperadenylation are major determinants of increased mRNA stability of CDR1 in azole-resistant clinical isolates of Candida albicans

• DOI: 10.1099/mic.0.035154-0
• Publication Date: 2009-11-13T01:53:35Z
• Authors: Raman Manoharlal; Jyotsna Gorantala; Monika Sharma; Dominique Sanglard; Rajendra Prasad
• Keywords: Azoles; 0301 basic medicine; 0303 health sciences; Antifungal Agents; Polymorphism, Genetic; RNA Stability; Homozygote; Loss of Heterozygosity; Membrane Transport Proteins; Polynucleotide Adenylyltransferase; Pancreatitis-Associated Proteins; RNA, Fungal; Microbial Sensitivity Tests; Fungal Proteins; 03 medical and health sciences; Candidiasis, Oral; Drug Resistance, Fungal; Candida albicans; Humans; RNA, Messenger; Cloning, Molecular; Poly A; 3' Untranslated Regions

Using genetically matched azole-susceptible (AS) and azole-resistant (AR) clinical isolates of Candida albicans , we recently demonstrated that CDR1 overexpression in AR is due to its enhanced transcriptional activation mRNA stability. This study examines the molecular mechanisms underlying stability isolates. Mapping 3′ untranslated region (3′ UTR) revealed it was rich adenylate/uridylate (AU) elements, possessed heterogeneous polyadenylation sites, had putative consensus sequences for RNA-binding proteins. Swapping heterologous chimeric lacZ – UTR reporter fusion constructs did not alter activity AS isolates, indicating cis -acting within itself are sufficient confer observed differential decay. Interestingly, poly(A) tail ∼35–50 % hyperadenylated as compared with C. polymerase ( PAP1 ), responsible adenylation, resides on chromosome 5 close proximity mating type-like MTL ) locus. Two different alleles, PAP1-a/PAP1-α were recovered from MTL-a/MTL-α while a single type allele PAP1-α MTL-α/MTL-α ). Among heterozygous deletions PAP1-a (Δ pap1-a/PAP1-α PAP1-a/ Δ pap1-α only former led relatively drug resistance, transcript isolate. suggests dominant negative role Taken together, our provides first evidence, knowledge, loss heterozygosity at locus linked hyperadenylation subsequent increased transcripts, thus contributing resistance.