a) Cre-loxP recombination scheme. Recombination between the promoter construct (padh1-loxP-kanMX6) and the gene construct (loxP-ura4-kanMX6) results in the formation of the rearrangement and ura4 expression. Black and grey boxes represent loxP sequences and circles indicate centromeres. ( + b) T5 and T7 have lower expression of the antibiotic resistance gene Kan r inserted near the breakpoint. Serial dilutions were spotted on plates containing 0, 100, 200 and 400 mg l −1 of geneticin and allowed to grow for 4 days at 32 °C. ( c) Schematic representation of genes near the breakpoints in the parental strain and their localization in T5 and T7. ( d) CRs cause changes to expression of genes near breakpoints. mRNA levels relative to controls near the breakpoint. Gene expression was assayed in cells that have grown in rich media (YES). Error bars represent s.e. of three to six independent experiments. (* P<0.05 according to Mann–Whitney U-test). ( e) Schematic representation of genes involved in responses to general stress in S. pombe and to ethanol stress in 45 S. cerevisiae in the parental strain and in T5 and T7. ( 44 f) Rearrangements cause changes in gene expression. T5 has lower gene expression upon exposure to 3% EtOH, whereas T7 is higher even before ethanol exposure. Genes are displayed by no particular order. Error bars represent s.e. of three to six independent experiments. Error bars represent s.e. (* P<0.05, ** P<0.01 according to Mann–Whitney U-test). In applying the very conservative Bonferoni correction, there is not enough power to detect statistical significance in our gene expression studies.