Original Article

CSU52, a novel regulator functions as a repressor of L-sorbose utilization in Candida albicans

Abstract

Background and Objectives: Monosomy of chromosome 5 associated with utilization of non-canonical sugar L-sorbose is one of the well-studied aneuploidies in Candida albicans. Stress-induced ploidy changes are crucial determinants for pathogenicity and genetic diversity in C. albicans. The five scattered regulatory regions (A, B, C, 135, and 139) comprising of two functionally redundant pathways (SUR1 and SUR2) were found to be responsible for the growth on L-sorbose. So far, three genes such as CSU51, CSU53 and CSU57 have been identified in region A, region 135 and region C, respectively. In this study we have verified the role of region B in this regulatory pathway.
Materials and Methods: We employed a combinatorial gene deletion approach to verify the role of region B followed by co-over expression studies and qRT-PCR to identify the regulatory role of this region.
Results: We confirmed the role of region B in the regulation of SOU1 gene expression. The qRT-PCR results showed that regulation occurs at transcriptional level along with other two regions in SUR1 pathway. A previously uncharacterized open reading frame in region B has been implicated in this regulation and designated as CSU52. Integrating multiple copies of CSU52 in the genome at tandem, suppresses the growth of recipient strain on L-sorbose, establishing it as a repressor of SOU1 gene.
Conclusion: This finding completes the identification of regulators in SUR1 pathway. This result paves the way to study the underlying molecular mechanisms of SOU1 gene regulation that in-turn helps to understand stress induced aneuploidy.

1. Berman J, Sudbery PE. Candida albicans: a molecular revolution built on lessons from budding yeast. Nat Rev Genet 2002;3: 918-930.
2. Kabir MA, Hussain MA, Ahmad Z. Candida albicans: a model organism for studying fungal pathogens. ISRN Microbiol 2012;2012: 538694.
3. Jones T, Federspiel NA, Chibana H, Dungan J, Kalman S, Magee BB, et al. The diploid genome sequence of Candida albicans. Proc Natl Acad Sci U S A 2004;101: 7329-7334.
4. Bennett RJ, Johnson AD. Completion of a parasexual cycle in Candida albicans by induced chromosome loss in tetraploid strains. EMBO J 2003;22: 2505-2515.
5. Rustchenko E. Chromosome instability in Candida albicans. FEMS Yeast Res 2007;7: 2-11.
6. Selmecki A, Forche A, Berman J. Aneuploidy and isochromosome formation in drug-resistant Candida albicans. Science 2006;313: 367-370.
7. Wellington M, Rustchenko E. 5-Fluoro-orotic acid induces chromosome alterations in Candida albicans. Yeast 2005;22: 57-70.
8. Kabir MA, Ahmad A, Greenberg JR, Wang YK, Rustchenko E. Loss and gain of chromosome 5 controls growth of Candida albicans on sorbose due to dispersed redundant negative regulators. Proc Natl Acad Sci U S A 2005;102: 12147-12152.
9. Greenberg JR, Price NP, Oliver RP, Sherman F, Rustchenko E. Candida albicans SOU1 encodes a sorbose reductase required for L-sorbose utilization. Yeast 2005;22: 957-969.
10. Ahmad A, Kravets A, Rustchenko E. Transcriptional regulatory circuitries in the human pathogen Candida albicans involving sense--antisense interactions. Genetics 2012;190: 537-547.
11. Ramon AM, Fonzi WA. Genetic transformation of Candida albicans. Methods Mol Biol 2009;499: 169-174.
12. Reddy PK, Pullepu D, Dhabalia D, Udaya Prakash SM, Kabir MA. CSU57 encodes a novel repressor of sorbose utilization in opportunistic human fungal pathogen Candida albicans. Yeast 2021;38: 222-238.
13. Sambrook JF, Russell DW (2001). Molecular cloning: a laboratory manual. 3rd ed. Cold Spring Harbor Laboratory Press. New York.
14. Mendes GP, Vieira PS, Lanceros-Méndez S, Kluskens LD, Mota M. Transformation of Escherichia coli JM109 using pUC19 by the Yoshida effect. J Microbiol Methods 2015;115: 1-5.
15. Mottola A, Schwanfelder S, Morschhäuser J. Generation of Viable Candida albicans mutants lacking the "Essential" protein kinase Snf1 by inducible gene deletion. mSphere 2020;5: e00805-20.
16. Sherman F. Getting started with yeast. Methods Enzymol 2002;350: 3-41.
17. Kabir MA, Rustchenko E. Determination of gaps by contig alignment with telomere-mediated chromosomal fragmentation in Candida albicans. Gene 2005;345: 279-287.
18. Cravener MV, Mitchell AP. Candida albicans culture, cell harvesting, and total RNA extraction. Bio Protoc 2020;10: e3803.
19. Schmittgen TD, Livak KJ. Analyzing real-time PCR data by the comparative C(T) method. Nat Protoc 2008;3: 1101-1108.
20. CLSI (2017). Performance standards for antifungal susceptibility testing of yeasts. 1 st ed. CLSI supplement M60. Wayne PA. Clinical and Laboratory Standards Institute.
21. Yang F, Zhang L, Wakabayashi H, Myers J, Jiang Y, Cao Y, et al. Tolerance to Caspofungin in Candida albicans is associated with at least three distinctive mechanisms that govern expression of FKS genes and cell wall remodeling. Antimicrob Agents Chemother 2017;61: e00071-17.
22. Leach MD, Farrer RA, Tan K, Miao Z, Walker LA, Cuomo CA, et al. Hsf1 and Hsp90 orchestrate temperature-dependent global transcriptional remodelling and chromatin architecture in Candida albicans. Nat Commun 2016;7: 11704.
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IssueVol 13 No 4 (2021) QRcode
SectionOriginal Article(s)
Published2021-08-11
DOI https://doi.org/10.18502/ijm.v13i4.6978
Keywords
Candida albicans; L-sorbose; Aneuploidy; Fungal gene expression regulation; Stress; Gene dosage

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Creative Commons License This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
How to Cite
1.
Pullepu D, Uddin W, Narayanan A, Kabir M. CSU52, a novel regulator functions as a repressor of L-sorbose utilization in Candida albicans. Iran J Microbiol. 2021;13(4):525-536.