Ecl1, a Regulator of the Chronological Lifespan of Schizosaccharomyces pombe, Is Induced upon Nitrogen Starvation

In fission yeast, ecl1(+) was identified as a novel factor that extends chronological lifespan when overexpressed. Ecl1 is a small protein consisting of 80 amino acids localized mainly in the nucleus. However, the mechanism by which it affects chronological lifespan has not been elucidated clearly. Here we analyzed the expression profile of Ecl1, especially as to cell cycle and growth phase, and found that it is induced upon nitrogen starvation. Then we analyzed the relevance of factors, Atf1, Ste11, and Tor1, which are known to be involved in the signaling of nitrogen starvation. Though the nitrogen starvation-induced expression of Ecl1 did not change in the atfA mutant, induction in both the ste11 Delta mutant and the tor1 Delta mutant showed a delay. Based on these observations, the regulation of Ecl1 is discussed.