Functional expression of chitinase and chitosanase, and their effects on morphologies in the yeast Schizosaccharomyces pombe

The chitinase A (chiA) gene from Enterobacter sp. G-1 and the chitosanase A (choA) gene from Matsue-bacter chitosanotabidus 3001 were expressed separately and simultaneously in the yeast Schizosaccharomyces pombe. The chiA gene was placed under the transcriptional control of the nmt1 promoter with the glutathione S transferase (GST), and the choA gene was expressed by the human cytomegalovirus (hCMV) promoter with the P factor secretion signal (P3). The expressed proteins of ChoA and GST-ChiA were enzymatical active and were detected as 34-kDa and 80-kDa, respectiveIy, by Western blot analysis. The transformant that expressed the choA gene was able to secrete ChoA efficiently into the culture medium with the specific activity of 102.36 U/mg protein. When the chiA gene was expressed in S. pombe, yeast cells grew slowly and cells became elongated, but when the choA gene was expressed, cells became swollen. Expression of both the chi4 and the choA genes resulted in elongated and fat cells.