This gene has a nearly identical homolog in C immitis, CIMG_0314

This gene has a nearly identical homolog in C. immitis, CIMG_03142, that was upregulated 3.6 fold in day 2 spherules and 3.39 fold in day 8 spherules. Whiston et al. also found it to be upregulated in spherules [13]. Another H. capsulatum gene that is required for yeast formation is α glucan synthase (AGS1) gene [62]. This enzyme catalyzes the production of α (1,3) glucan in the cell wall that obscures the β (1,3) glucan and prevents activation of innate immunity via the dectin-1 receptor [62]. C. immitis has an AGS1 gene (CIMG_13256) that was upregulated in the day 8 spherule (2.48 fold) but not day 2 spherules. Whiston et al. found this gene to be upregulated

1.93 fold in spherules compared to mycelia [13]. There is no literature describing the relative amounts of α (1,3) glucan and β (1,3) glucan in C. immitis mycelia or spherules. We know, however, that there is enough exposed β (1,3) glucan Selleckchem Nirogacestat in Coccidioides spherules to stimulate macrophages to produce cytokines via dectin-1 [63]. Two genes buy Stattic coding for transcription factors, Ryp2 and Ryp3, have been found to be essential for conversion from filaments to yeast in H. capsulatum[64]. These genes are overexpressed in the yeast phase of H. capsulatum[64]. C. immitis has nearly identical this website homologs of these genes but they were not overexpressed

in either day 2 or day 8 spherules, suggesting that they may not be required for the transformation from mycelium to spherule. Gene disruption experiments in B. dermatitidis have shown that a histidine kinase, DRK1, is required for the transformation from filaments to yeast [65]. It is not clear from the literature whether or not this gene is overexpressed in the B. dermatitidis yeast phase. C. immitis has a very closely related homolog of this gene (CIMG_04512) but it was not up or down regulated in day 2 or day 8 spherules. In another dimorphic pathogenic fungus, S. schenckii, the calcium/calmodulin kinase I gene (SSMK1) was found to be required for formation of yeast [53]. There are two genes in C. immitis that are highly homologous to the S. schenckii SSMK1 gene; neither

one of these was up- or downregulated in day 2 or day 8 spherules. A number of studies have been done studying the transcriptome of P. brasiliensis[66, 67]. One study identified the 4-HPPD gene to be required for P. brasiliensis conidia to convert to yeast [66]. They found that the 4-HPPD gene expression was upregulated in the yeast form and that a biochemical inhibitor of this enzyme, nitisinone, inhibited mycelium conversion to yeast. 4-HPPD (E.C. 1.13.1127) is an enzyme that converts 4-hydroxyphenylpyruvate to homogentisate that is involved in the synthesis of tyrosine, phenylalanine, and ubiqinone (KEGG, whttp://​www.​genome.​jp/​keg). There are two homologs of the 4-HPPD in the C. immitis genome, which have significantly different sequences.

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