2259 11 archive 2 disk0/00/00/22/59 2008-07-03 07:03:15 2008-07-03 07:03:15 2008-07-03 07:03:15 article show Abdul Munir Abdul Murad Farah Diba Abu Bakar Brown, J.P. Universiti Kebangsaan Malaysia. Faculty of Medicine. Dept, of Biocience and Biotechnology Universiti Kebangsaan Malaysia. Faculty of Medicine. Dept, of Biocience and Biotechnology University of Aberdeen. Institute of Medical Sciences. 2Department of Molecular and Cell Biology pub Q R none Candida albicans, MET3 promoter, gene overexpression, promoter strength We would like to thank Universiti Kebangsaan Malaysia and The Ministry of Science, Technology and Innovation (IRPA 09-02-02-0103-EA255) for funding this research. AJPB was supported by The Wellcome Trust (Grant No: 055015). The strength of Candida albicans MET3 promoter to regulate the expression of a gene in C. albicans was investigated in this study. A gene encoded for a transcriptional repressor for filamentous growth, NRG1, was cloned downstream of the MET3 promoter in C. albicans integrative vector, pCaEXP to produce a pMET3p-NRG plasmid. The plasmid was linearised with Stu1 and transformed into C. albicans CAI4. Polymerase chain reaction (PCR) and Southern blotting confirmed that the overexpression cassette integrated correctly into C. albicans genome at the RP10 locus. Northern blot analysis showed that the level of NRG1 overexpression in the mutant increased by only 0.5 fold compared to the wild type and to the control mutant, C. albicans CAI4 harboring an integrated pCaEXP. This data correlates with the inability of the mutant to sustain itself in yeast morphological forms, which should take place if the NRG1 gene is highly expressed, when cells were grown in filamentous inducing medium. 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