A peptide derived from pICln induced a strong hypotonic resistance in Escherichia coli cells

We demonstrated previously that expression of rat pICln in Escherichia coli conferred a strong resistance to hypotonic stress. To define the intramole cular functional domain responsible for the resistance, molecular dissectio n of pICln was performed and the obtained peptides were expressed in E. col i. The cells expressing the peptides were exposed to a hypotonic solution, and their 'survival rates' were observed. The cells expressing only the pep tides including the second acidic domain of pICln exhibited significantly h igher 'survival rates' after hypotonic stress. The functional domain agains t hypotonicity was finally narrowed down to a peptide consisting of a 46-am ino acid residue, P107-152. We conclude that the expression of P107-152 in E. coli cells could enhance their resistance to a hypotonic environment. (C ) 2000 Elsevier Science Inc. All rights reserved.