EFFECT OF OVER-EXPRESSED HSP26 ON CELL-GROWTH OF YEAST

Mammalian small heat shock protein (s-hsp) has been suggested to parti cipate not only in stress tolerance but also in the growth regulation and differentiation of cells. To confirm the role of s-hsp in cell gro wth, we investigated the relationship between the expression of hsp26 and yeast cell growth. Cells lacking constitutive hsp70, ssa1ssa2, hav e been known to have a poor growth rate and to over-express hsp26 and some other hsps, We obtained several cell clones of ssa1ssa2 whose dou bling times were different from one another. The amount of hsp26 was c losely linked to the doubling time of ssa1ssa2 cells. This result sugg ests that the expression of hsp26 modulates the growth rate of yeast c ells lacking constitutive hsp70, similarly to mammalian cells.