Cell cycle dependency of rice alpha-amylase production in a recombinant yeast

The cell cycle dependency of rice alpha-amylase production in Saccharomyces cerevisiae was investigated using synchronous and arrested cultures. The results of two separate synchronous cultures, using alpha-mating factor and a cdc28 mutant, indicated that the rice alpha-amylase-specific production rate is not constant during the cell cycle. The specific production rates during G1, S, and M phases were then ascertained by inhibiting the progression of the cell cycle using alpha-mating factor, hydroxyurea, and nocodazole, respectively. The specific production rate was found to be maximal during the M phase. The increase in the specific production rate during the M phase was confirmed from the accumulation of M-phase cells using a cdc15 mutant. The intracellular content of rice alpha-amylase was also measured during the cell cycle. Like the specific production rate, the intracellular content was found to fluctuate throughout the cell cycle, and to reach a maximum during M phase.