| Abstract: | Genomic DNA encoding a class IV chitinase was cloned from yam (Dioscorea opposita Thunb) leaves in previous research (Biosci. Biotechnol. Biochem., 68, 1508–1517 (2004)). But this chitinase had an additional sequence composed of eight amino acids (a C-terminal extension) at the C-terminal, compared with class IV chitianses from other plants. In order to clarify the role of this C-terminal extension in cellular localization, plants and suspension-cultured cells of Nicotiana tabacum were transformed with either the cloned yam class IV chitinase gene carrying the C-terminal extension or its truncated gene by the Agrobacterium-mediated method, and then their localization was investigated. The results suggest that the C-terminal extension of yam class IV chitinase plays a role as a targeting signal for plant vacuoles. This is the first report presenting the existence of vacuolar type class IV chitinase. |
