Christodoulidou A, Bouriotis V, Thireos G
Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-HELLAS, Greece.
J Biol Chem. 1996 Dec 6;271(49):31420-5. doi: 10.1074/jbc.271.49.31420.
The formation of the ascospore wall of Saccharomyces cerevisiae requires the coordinate activity of enzymes involved in the biosynthesis of its components such as chitosan, the deacetylated form of chitin. We have cloned the CDA1 and CDA2 genes which together account for the total chitin deacetylase activity of the organism. We have shown that expression of these genes is restricted to a distinct time period during sporulation. The two genes are functionally redundant, each contributing equally to the total chitin deacetylase activity. Diploids disrupted for both genes sporulate as efficiently as wild type cells, and the resulting mutant spores are viable under standard laboratory conditions. However, they fail to emit the natural fluorescence of yeast spores imparted by the dityrosine residues of the outermost ascospore wall layer. Moreover, mutant spores are relatively sensitive to hydrolytic enzymes, ether, and heat shock, a fact that underscores the importance of the CDA genes for the proper formation of the ascospore wall.
酿酒酵母子囊孢子壁的形成需要参与其成分生物合成的酶的协同作用，这些成分包括壳聚糖，即几丁质的脱乙酰化形式。我们克隆了CDA1和CDA2基因，它们共同构成了该生物体的总几丁质脱乙酰酶活性。我们已经表明，这些基因的表达仅限于孢子形成过程中的一个特定时间段。这两个基因在功能上是冗余的，对总几丁质脱乙酰酶活性的贡献相同。两个基因都被破坏的二倍体与野生型细胞一样有效地形成孢子，并且在标准实验室条件下，产生的突变孢子是有活力的。然而，它们无法发出由最外层子囊孢子壁层的二酪氨酸残基赋予的酵母孢子的天然荧光。此外，突变孢子对水解酶、乙醚和热休克相对敏感，这一事实强调了CDA基因对子囊孢子壁正确形成的重要性。
