The inducible N-acetylglucosamine catabolic pathway gene cluster in Candida albicans: discrete N-acetylglucosamine-inducible factors interact at the promoter of NAG1.
The catabolic pathway of N-acetylglucosamine (GlcNAc) in Candida albicans is an important facet of its pathogenicity. One of the pathway genes, encoding glucosamine-6-phosphate deaminase (NAG1) is transcriptionally regulated by GlcNAc. Sequence analysis of a 4-kb genomic clone containing NAG1 indicates that this gene is part of a cluster containing two other genes of the GlcNAc catabolic pathway, i.e., DAC1, GlcNAc-6-phosphate deacetylase, and HXK1, hexokinase. All three genes are temporally and coordinately induced by GlcNAc suggesting a common regulatory mechanism for these genes. The NAG1 promoter is up-regulated when induced by GlcNAc in C. albicans but not in Saccharomyces cerevisiae. In vivo analysis of the deletion constructs delineated the minimal promoter to -130 bp and mapped two regions at -200 and -400 bp upstream of +1 (ATG) responsible for GlcNAc induction. Gel mobility-shift assays and "footprinting" (DNase protection method) analyses revealed two regions, 5'-GGAGCAAAAAAATGT 3' (-164 to -150, box A) and 5'-ACGGTGAGTTG 3' (-291 to -281, box B), that are recognized and bound by at least two inducible activator proteins directing the regulation of gene expression.
Kumar
M J
MJ
Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
Jamaluddin
M S
MS
Natarajan
K
K
Kaur
D
D
Datta
A
A
D000117:Acetylglucosamine / Q000378:metabolism*; D019747:Aldose-Ketose Isomerases / Q000235:genetics; D000581:Amidohydrolases / Q000235:genetics*; D002176:Candida albicans / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D017931:DNA Primers; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D006593:Hexokinase / Q000235:genetics*; D005810:Multigene Family; D011401:Promoter Regions, Genetic
D017931:DNA Primers; D006593:Hexokinase; D000581:Amidohydrolases; C018717:N-acetylglucosamine-6-phosphate deacetylase; C020582:glucosamine-6-phosphate isomerase; D019747:Aldose-Ketose Isomerases; D000117:Acetylglucosamine