Involvement of ADH1, IPT1 and PMT Genes in Candida albicans Pathogenesis - Biotechnology of Fungal Genes - page 81

mutant was unable to promote gingival cell necrosis or disturb gingival
tissue structure (Rouabhia et al. 2005). The non-virulence of Pmt 1 may thus
be due to its incapacity adapting to hyphal morphogenesis, its leakage
of cell wall proteins, such as chitinase, its sensitivity to antifungal drugs
and its lack of proper adhesion to mammalian cells (Sanchez et al. 2004,
Timpel et al. 1998). In this study, the Pmt 1 mutant failed to form hyphae
when in contact with the EHOM assay ( Fig. 5).
Pmt 2 gene
This gene plays an active role in C. albicans growth and pathogenesis. It
has been reported that C. albicans strain lacking both alleles of Pmt 2 is not
viable. Heterozygous Pmt 2/ Pmt 2 strain displays severe growth defects
under stress conditions (Prill et al. 2005). Deletion of a single Pmt 2 allele
also resulted in signifi cantly reduced virulence in vitro and in vivo infection
models. Using a mouse model, Pmt 2/ Pmt 2 heterozygous mutant was
shown to not promote animal death, even if the Candida cells persisted
in vital tissues such as the kidneys and the brain (Rouabhia et al. 2005).
Pmt 2 heterozygous strain is partially defective in protease secretion.
Interestingly, in an in vitro tissue model, Pmt 2/ Pmt 2 heterozygous strain
caused little structural damage to the tissue (Rouabhia et al. 2005).
Pmt 4 gene
Pmt4 gene is essential in C. albicans growth. Pmt4 gene promotes C.
albicans growth along with PMT 1 gene. Pmt4 mutant was shown to display
high aggregation yet reduced hydrophobicity and alterations of the cell
wall. Under appropriate culture conditions, Pmt 4 mutant was able to
form hyphae as a parental strain (Willger et al. 2009), which suggests its
implication in C. albicans virulence. Pmt 4 mutant was also shown to be
sensitive to several anti-fungal drugs. Using an engineered human oral
mucosa, we were able to show that Pmt 4 mutants were almost as virulent
as the control strain in provoking signifi cant damage to the epithelial
structure (Rouabhia et al. 2005, Fig. 5). Based on these results, it will be
important to further investigate the role of Pmt 4 and PMT 6 in C. albicans
pathogenesis.
Pmt 5 gene
Pmt5 is another isoform that may be involved in C. albicans virulence .
Genomic sequencing revealed that PMT 1 and Pmt5 proteins constitute one
subgroup (Prill et al. 2005). Inactivation of the Pmt 5 gene (mutation) did
not hamper hyphal formation and Pmt5 mutant was not more sensitive