Yeast Morphogenesis

In C. albicans, dimorphic switching is controlled by a number of transcriptional regulators that integrate environmental signals. The Efgl (APSES protein), Cphl (Ste12 homologue), and Tecl (ATTS protein) regulators promote filamentation while Tupl represses filamentation (Lengeler et al., 2000; Schweizer et al., 2000). In P. marneffei, StuA (APSES protein) and StlA (Ste12 homologue) do not play a role during dimorphic switching (Borneman et al., 2001, 2002a). In contrast, the AbaA (ATTS protein) is required for the coupling of nuclear and cellular division during hyphal-yeast dimorphic switching, in addition to its role in asexual development, such that abaA deletion mutants produces multinucleate arthroconidiating hyphae and yeast cells (Figure 9.4) (Borneman et al., 2000). In P. marneffei, TupA is required to repress yeast morphogenesis at 25°C (Todd et al., 2003).

Morphogenetic changes during hyphal to yeast dimorphic switch require the CDC42-like small GTPase CflA and the Ras GTPases RasA in P. marneffei. Mutants affected in cflA function show significant defects in yeast cell polarization, shape, and division (Boyce et al., 2001), Mutations in the rasA gene of P. marneffei also affect yeast cell polarization, shape, and division and it is clear that this is predominantly due to RasA acting upstream of CflA (Boyce et al., 2005). However, there are subtle differences in some of the phenotypes seen in rasA and cflA mutants which suggest that RasA may also affect yeast morphogenesis via a second, CflA-independent, mechanism (Boyce et al., 2005).

Cure Your Yeast Infection For Good

Cure Your Yeast Infection For Good

The term vaginitis is one that is applied to any inflammation or infection of the vagina, and there are many different conditions that are categorized together under this ‘broad’ heading, including bacterial vaginosis, trichomoniasis and non-infectious vaginitis.

Get My Free Ebook

Post a comment