In this study, we construct an evaluation system of vesicle transport for screening of inhibitors of tip growth as novel antifungal agents with use of Saccharomyces cerevisiae and Candida albicans. We select a BGL (β-glucanase) as a transported protein to fungal tip and construct BGL-GFP fusion protein to observe the transport. After investigation of properties of transportation of the fusion protein, we use the system as a screening of antifungal agents.
Mycosis is an infection to human caused by fungi, such as mold and yeast and deep mycosis has become a particularly serious problem. However, the types of antifungals are few and the treatment options are limited. Since fungi and human cells are eucaryotes, existing antifungal agents have also been reported to have side effects on humans. Furthermore, the emergence of resistant fungi has become a problem due to the long-term use of the drug. From those problems, the development of an antifungal agent has a new mechanism of action is required.
We focused on tip growth which is a specific growth system of fungi as an antifungal target. We consider that targeting vesicle transport for tip growth will provide selective toxicity to fungi. Therefore, in this study, we develop a novel evaluation system of vesicle transport to the fungal tip. It has been reported that BGL2 is transported from the inside of the cell to the growth point. An evaluation system for visualizing vesicle transport was constructed by fusing green fluorescent protein GFP downstream of BGL2 to be transported to the growth point by expression of the protein in S. cerevisiae. Using this evaluation system, vesicle transport inhibitory activity was screened for 163 kinds of herbal medicine extracts. As a result, vesicle transport inhibitory activity was observed in 8 types. In addition, we attempted to construct a similar evaluation system using C. albicans and aimed to evaluate fungi that form hyphae that cause actual mycosis.

Eriko Mori

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