It was demonstrated recently that three histidine kinases genes in Candida albicarrs contribute to virulence, indicating the importance of signaling pathways regulated by histidine kinases. In the present study, using degenerate primers of highly conserved regions of a histidine kinase, RT-PCR was performed with cDNA of A.fumigatus as a template. One of the PCR products was cloned and sequenced. After Blast analysis, it was demonstrated to be highly homologous to the two component histidine kinase tesA gene of Aspergillus. A murine model of invasive pulmonary aspergillosis was established. After inoculation, the lungs of infected and non-infected animals were obtained and incubated for 2h at 37Â°C in digestion buffer containing collagenase (Gibco) and trypsin. The pulmonary cells were removed by passing the suspension through a sieve. The non-filterable hyphae were treated with deoxygenated sodium cholate for ISmin. Total RNA of A. fumigatus isolated from the infected tissues and cultures in vitro was extracted. By northern blot, a 3.0 kb (approximate) transcript of mRNA was detected corresponding to the putative histidine kinase gene. It was demonstrated that that gene was expressed at higher levels in vivo than in vitro. The results suggest that this gene contributes to the survival of A. fumigatus in vivo and is potential a virulence gene.
Full conference title:
Focus on Fungal Infections 11, March 14-16 2001
- Focus on Fungal Infection 11 (2001)