Characterization and metal-induced gene transcription of two new copper zinc superoxide dismutases in the solitary ascidian Ciona intestinalis

Abstract

a b s t r a c tAntioxidant enzymes are known to protect living organisms against the oxidative stress risk, also induced by metals. In the present study, we describe the purification and molecular characterization of two Cu,Zn superoxide dismutases (SODs), referred to as Ci-SODa and Ci-SODb, from Ciona intestinalis, a basal chordate widely distributed in temperate shallow seawater. The putative amino acid sequences were compared with Cu,Zn SODs from other metazoans and phylogenetic analyses indicate that the two putative Ci-SODs are more related to invertebrate SODs than vertebrate ones. Both phylogenetic and preliminary homology modeling analyses suggest that Ci-SODa and Ci-SODb are extracellular and intracellular isoform, respectively. The mRNA of the two Cu,Zn SODs was localized in hemocytes and in ovarian follicular cells, as revealed by in situ hybridization. The time course of SOD mRNA levels in the presence of three different metals showed upregulation of ci-soda and inhibition of ci-sodb. Spectrophotometric analysis confirms the presence of SOD activity in Ciona tissues. Our in silico analyses of the ci-soda promoter region revealed putative consensus sequences similar to mammalian metal-responsive elements (MRE), suggesting that the transcription of these genes directly depends on metals. These data emphasize the importance of complex metal regulation of ci-soda and ci-sodb transcription, as components of an efficient detoxification pathway allowing the survival of C. intestinalis in continued, elevated presence of metals in the environment.

Copper/Zinc Superoxide Dismutase from the Crocodile Icefish Chionodraco hamatus: Antioxidant Defense at Constant Sub-Zero Temperature

“…Virtually all eukaryotic cells contain Cu,Zn SODs [37][38][39][40][41][42], as well as other anti-stress proteins that allow species to withstand environmental stresses of both natural and anthropogenic origin [43][44][45][46][47][48][49][50][51][52][53]. Our results indicated that a gene coding for cytosolic Cu,Zn SOD is present in the genome of the Antarctic icefish C. hamatus and is expressed as active protein in various organs.…”

Dietary myo-inositol modulates immunity through antioxidant activity and the Nrf2 and E2F4/cyclin signalling factors in the head kidney and spleen following infection of juvenile fish with Aeromonas hydrophila

“…not only at the gene transcriptional level but also at the posttranscriptional level (i.e., translation or post-translational modification) as indicated by Ferro and his co-authors [65]. Nrf2 is involved in the regulation of antioxidant enzyme gene transcription in fish [71].…”

“…These results might represent a feedback mechanism that cause a decrease in the GSH content that requires an increase in GR for re-generation when the fish are subjected to MI deficiency. SOD is a free oxygen radical-scavenging enzyme that is responsible for the first line of defence against ROS [65]. Eukaryotes possess two major types of SOD: the cytoplasmic form CuZnSOD and the mitochondrial form MnSOD [66].…”

Soyabean glycinin depresses intestinal growth and function in juvenile Jian carp (Cyprinus carpiovar Jian): protective effects of glutamine

“…Similar results were observed in our previous study with fish exposed to another dietary antinutrient factor β-conglycinin (24) . Second, it might be related to influences on enzyme activities that occurred not only at the gene transcriptional level but also at the post-transcriptional (such as translation, post-translational modification and so on) levels, just as Ferro et al (55) indicated. The GSTs represent an important group of enzymes that detoxify both endogenous compounds and foreign chemicals such as pharmaceuticals and environmental pollutants (56) .…”