Transgenic analysis of the cSOD-null phenotypic syndrome in Drosophila

Abstract

Cu-Zn superoxide dismutase (cSOD) is an enzyme of critical importance for the inactivation of superoxide radicals generated by cellular metabolic processes. A phenotypic syndrome has been characterized for homozygotes for a null mutation of the Drosophila cSOD gene, many features of which may be relevant to current studies of cSOD mutations in mammals. However, it was possible that some of the features of this syndrome were at least partially attributable to genetic background differences between control and mutant strains. The results reported in this paper document that the previously described features of the cSOD-null phenotype, namely (i) adult sensitivity to paraquat, (ii) male sterility, (iii) female semisterility, (iv) adult life-span reduction, (v) adult hyperoxia sensitivity, (vi) larval radiation sensitivity, and (vii) developmental sensitivity to glutathione depletion, are all rescued by a cSOD+ transgene in a controlled cSOD-null genetic background. This clearly confirms that the phenotype is largely attributable to the cSOD mutation per se. We describe two new features of the cSOD-null phenotype, namely (viii) adult sensitivity to glutathione depletion, and (ix) adult sensitivity to ionizing radiation, which are ameliorated by the cSOD+ transgene. The distinct sensitivity of cSOD-deficient individuals, and the uniform resistance of the cSOD+ control strains, clearly establish the requirement for cSOD in protection against intrinsic and applied oxygen stress and set the stage for tissue-specific expression studies with the goal of elucidating the critical target(s) of damage in cSOD-deficient animals.

Superoxide dismutase and catalase: tissue activities and relation with age in the long-lived species Margaritifera margaritifera

“…There are experimental evidences supporting this from many years ago, both in laboratory mice (Kellog and Fridovich, 1976) and humans and fruit flies (Parkes et al 1998;Rusting 1998). Furthermore, SOD and CAT are believed to play a key role in the enzymatic defence of the cells against oxygen toxicity, this belief being substantiated by the ubiquitous presence of these enzymes in aerobic organisms (Peskin et al, 1977;Longa et al, 1994;García Martínez et al, 1995;Peskin, 1997;Delcourt, 1999;Hernández-Nistal et al, 2002).…”

“…Cu,Zn-SOD has been related to the life-span and the metabolic rate in primate species (Tolmasoff et al, 1980;Cutler, 1983). In Drosophila, the biological effects of the absence of Cu,Zn-SOD have been reported, namely reduced viability, dramatically shortened life span, adult sensitivity to paraquat, low male and female fertility, etc (Parkes et al, 1998). Effects of reduced fertility and high mortality of embryos have been described in mice with a modified Cu,Zn-SOD gene ("knock-out females", Miller et al, 1993;Ho et al, 1998).…”

Genetic Bases of Oxidative Stress Resistance and Life Span in Drosophila

“…Stress resistance of flies has been measured by counting the number of survivals at a fixed time point after treatment with varied strength stress sources, such as oxidative chemicals, starvation, or hyperoxia [3,27,38]. Alternatively, survival curves have been determined under a fixed strength of stress and by counting the number of survivals following a time course [9,24].…”

“…A null mutation has been shown to induce hypersensitivity to paraquat, a free radical generator, and life span shortening [2]. Hypersensitivities to hyperoxia, glutahione depletion, and ionizing radiation were rescued by a wild-type Cu/Zn SOD transgene [3]. Introduction of additional copies of the Cu/Zn-SOD gene did not show a marked increase in life span [4,5].…”

Profiling Cu,Zn-superoxide dismutase expression in Drosophila melanogaster—a critical regulatory role for intron/exon sequence within the coding domain

“…In mouse knockouts, a higher mortality rate was noted as well as a greater propensity to suffer brain damage in response to ischemia (Chan et al, 1995). Partial or full rescue of these defects was possible using SOD1 transgenes (Parkes et al, 1998a;Reveillaud et al, 1991).…”