Effect of the copper-responsive factor Cuf1 on the capsule biosynthesis in Cryptococcus neoformans.
OBJECTIVE
Cryptococcus neoformans is an opportunistic human fungal pathogen that primarily infects immunocompromised patients. The most distinctive feature of C. neoformans is that it contains a highly regulated major virulence factor, the polysaccharide capsule. We demonstrate in this paper that a copper-dependent transcription factor gene CUF1 has a negative role in capsule biosynthesis.


METHODS
Colony morphology, Indian inking staining microscopy, volume of cell suspension observation, weight of capsule produced by the disruption mutant of CUF1 and the wild type control.


RESULTS
The mutant produced a mucoid large colonies compared to that of the wild type. Capsule size was larger as shown by microscopy. The mutant had a larger volume with the same number of cells. And the mutant produced more capsule as determined by weight of dried extracellular polysaccharides. Iron repletion could suppress the capsule overproduction phenotype of the deltacuf1 mutant.


CONCLUSIONS
The copper responsive transcription factor 1 (Cuf1) negatively regulates capsule biosynthesis in C. neoformans. Cuf1 may act via modulating iron acquisition through the high-affinity iron uptake pathway.
Jiang
Nan
N
Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China. jiangnan82@yahoo.cn
Liu
Xiaoguang
X
Pan
Jiao
J
Wang
Yajie
Y
Zhu
Xudong
X
D003300:Copper / Q000378:metabolism*; D003455:Cryptococcus neoformans / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D009154:Mutation; D011134:Polysaccharides / Q000096:biosynthesis*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D005656:Fungal Proteins; D011134:Polysaccharides; D014157:Transcription Factors; D003300:Copper