The sensitivity to UV and DEB of nine temperature-sensitive mutants was investigated. All prt and four cdc mutants (cdc4, cdc7, cdc8, cdc28) showed a higher level of sensitivity to UV than the wild type strain. Three mutants cdc7, cdc9 and prt1 are more sensitive than the wild type to DEB, but only two cdc7 and prt1 are sensitive to UV and DEB. Treatment with restrictive temperature increases the sensitivity after UV treatment of cdc9, cdc21, prt1, prt3 and after DEB treatment of cdc28 and all prt mutants.