The use of global transcriptional analysis to reveal the biological and cellular events involved in distinct development phases of Trichophyton rubrum conidial germination

We have developed a cDNA microarray containing 10250 ESTs to monitor the transcriptional strategy of conidial germination. A total of 1561 genes that had their expression levels specially altered in the process were obtained and hierarchically clustered with respect to their expression profiles. By functional analysis, we provided a global view of an important biological system related to conidial germination, including characterization of the pattern of gene expression at sequential developmental phases, and changes of gene expression profiles corresponding to morphological transitions. We matched the EST sequences to GO terms in the Saccharomyces Genome Database (SGD). A number of homologues of Saccharomyces cerevisiae genes related to signalling pathways and some important cellular processes were found to be involved in T. rubrum germination. These genes and signalling pathways may play roles in distinct steps, such as activating conidial germination, maintenance of isotropic growth, establishment of cell polarity and morphological transitions.Our results may provide insights into molecular mechanisms of conidial germination at the cell level, and may enhance our understanding of regulation of gene expression related to the morphological construction of T. rubrum.Trichophyton rubrum is a worldwide pathogen causing various superficial infections, accounting for at least 60% of dermatophytosis, such as tinea capitis, tinea corporis, tinea inguinalis, tinea manus, tinea unguium and tinea pedis [1-4]. This pathogen, which normally causes well-characterized superficial infections, also produces skin infections in unusual parts of the body in immunodepressed patients [5-7]. T. rubrum has a relatively simple and non-sexual stage life-cycle. Similar to numerous other filamentous fungi, it forms a mycelial colony via hyphal tip growth, branching and hyphal fusion. T. rubrum produces numerous asexual multinucleate spores, called macroconidia or arthroconidia, which are con