Overexpression of Ecl1-family genes (ecl1 +, ecl2 +, and ecl3 +) results in the extension of the chronological life span in Schizosaccharomyces pombe. However, the mechanism for this extension has not been defined clearly. Ecl1-family proteins consist of approximately 80 amino acids, and four cysteine residues are conserved in their N-terminal domains. This study focused on the Ecl1 protein, mutating its cysteine residues sequentially to confirm their importance. As a result, all mutated Ecl1 proteins nearly lost the function to extend the chronological life span, suggesting that these four cysteine residues are essential for the Ecl1 protein. Utilizing ICP-AES (inductively coupled plasma atomic emission spectroscopy) analysis, we found that wild-type Ecl1 proteins contain zinc, while cysteine-mutated Ecl1 proteins do not. We also analyzed the effect of environmental zinc on the chronological life span. We found that zinc limitation extends the chronological life span, and this extension depends on the Ecl1-family proteins.
Keywords: Ecl1; Fission yeast; Life span; Schizosaccharomyces pombe; Zinc.