Penicillium marneffei SKN7, a novel gene, could complement the hypersensitivity of S. cerevisiae skn7 Disruptant strain to oxidative stress.

Penicillium marneffei is an intracellular fungal pathogen. Being resistant to the reactive oxygen species (ROS) produced by phagocytes is a key step to the surviving of P. marneffei within the phagocytes, as well as its invasion to the host. SKN7, a transcription factor, contributes to the oxidative stress response in yeasts. We cloned the SKN7 ortholog in P. marneffei and compared its transcription on both mycelial and yeast phase, identified its function by complement the S. cerevisiae skn7 disruptant strain. The result showed the full sequence of SKN7 gene was about 2.5 kb, open reading frame extended to 1,845 bp and encoded a putative protein of 614 amino acids. Comparative analysis of the nucleotide sequence of genomic DNA and cDNA confirmed the presence of four introns and two highly conserved HSF-DNA-bind and REC domain. The deduced amino acid sequence was homologous to SKN7 from other fungi. Further, P. marneffei cDNA can partly complement S. cerevisiae skn7 disruptant strain, which was not viable in the presence of 2.5 mM H2O2. The expression level of SKN7 on the two phases, however, had no difference. These results indicated that P. marneffei SKN7 could response to oxidative stress and it was not a phase-specific gene.