Drosophila larvae deficient for superoxide dismutase activity are thermosensitive but show normal heat shock response

Abstract

Effects of deficiency for Cu-Zn superoxide dismutase (SOD) enzyme (EC 1.15.1.1) activity on thermosensitivity and heat shock response in Drosophila melanogaster were examined using a null allele (cSOD^nI08) of the gene coding for this enzyme activity. The CSODⁿ¹⁰⁸ homozygous larvae were poorly viable at 31°C while the CSODⁿ¹⁰⁸ heterozygotes had only a slightly reduced viability when compared with that at 21°C, indicating that deficiency for SOD activity makes the larvae thermosensitive. Deficiency for Cu-Zn SOD neither affected the inducibility of heat shock genes by temperature stress nor caused heat shock genes to express constitutively. In this sense, the accumulation of superoxide ions in SOD-deficient larvae did not mimic temperature stress. Thus the observed thermosensitivity of SOD-deficient larvae does not appear to be due to any aberration in the heat shock response.