Poster abstracts
Poster number 67 submitted by Michael Hrabak
Pseudouridine synthase 1 becomes localized more to the cytoplasm during stress in C. albicans
Michael R. Hrabak (Department of Biology Ball state), Douglas A. Bernstein (Department of Biology Ball state)
Abstract:
Pseudouridine is a crucial RNA modification found in all domains of life. Pseudouridine synthases (Pus) carry out this modification. Most investigations into these enzymes in fungi have been completed in the model S. cerevisiae. Relatively little is known about this process in the opportunistic pathogen C. albicans. C. albicans is a diploid fungus and thus has two alleles for almost all genes, including PUS1, a pseudouridine synthase. In S. cerevisiae, Pus1 modifies several sites on tRNA. S. cerevisiae Pus1 also plays a role in the nuclear export of tRNAs; thus, Pus1 localizes to the nucleus. PUS1 is nonessential for growth under optimal growth conditions. However, the loss of PUS1 displays a growth delay at elevated temperatures. Other Pus enzymes have also demonstrated sensitivity to elevated temperatures and other stress conditions, indicating an importance of these enzymes for cellular health during stress conditions. Here, we analyzed the localization of the two C. albicans Pus1 proteins under stress conditions caused by heat, cold, and hydrogen peroxide. We also analyzed the localization of the two proteins during exposure to metals such as lead, chromium, and zinc. We tagged Pus1a or Pus1b with GFP and measured the fluorescent intensities inside the nucleus and the cytoplasm, generating a cytoplasmic-to-nuclear ratio. We used this ratio to compare the localization of the proteins during different stress responses. Our results demonstrated increased cytoplasmic localization during heat stress for Pus1a and Pus1b. Our results demonstrated decreased cytoplasmic localization for both Pus1a and Pus1b during chromium exposure. Interestingly, the two proteins differed in cytoplasmic localization levels when treated with hydrogen peroxide, lead nitrate, and zinc, suggesting distinct roles for Pus1a and Pus1b.
Keywords: Pseudouridine synthase, C albicans