Summer Research Fellowship Programme of India's Science Academies

Understanding the role of Transcription Factor Network Controlling Iron Homeostasis

Akshay Udayashankar

Dept. of Biotechnology, PES University, 100 Feet Ring Road, BSK III Stage, Bangalore-560085

Dr. Krishnamurthy Natarajan

School of Life Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, Delhi 110067


Candida albicans is a commensal, opportunistic pathogen that can live in the human host at low as well as high iron concentrations. Various transcription factors and genes are responsible for their survival and virulence under varying iron level conditions. Iron homeostasis in C. albicans is regulated in low iron conditions via mechanisms that increase iron acquisition and decrease iron utilization. SEF1 codes for a Cys6Zn2 DNA binding protein which has a role in activating transcription of iron uptake genes in iron poor conditions such as in the host bloodstream and internal organs. Cap2/Hap43 is another regulatory complex wherein Cap2 controls the expression of HAP2, HAP32, HAP5 , the core components of HAP regulatory complex. In this summer, we are studying the regulatory network between the Sef1 and Cap2-HAP complex. Towards this end, we are developing double knockout mutants viz, sef1Δ/sef1Δ in either cap2Δ/cap2Δ or hap5Δ/hap5Δ mutant strain backgrounds to study their combined effects on the survival of C. albicans under low iron conditions. The sef1, cap2 and hap5 mutants have been studied, but a combination of these mutations have not been made thus far. Through the combined gene deletion analysis, we have checked for phenotypic growth defect of the double gene deleted mutant in comparison to individual mutants and observed a noticeable defect in certain low and high iron condition media. This is sufficient evidence to prompt furthur study on the combined gene deletion analysis.

Keywords: Gene knockout, sef1Δ/SEF1hap5Δ/Δ, cap2Δ/cap2Δ sef1Δ/sef1Δ, growth defect.

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