Cytosolic manganese superoxide dismutase genes from the white shrimp Litopenaeus vannamei are differentially expressed in response to lipopolysaccharides, white spot virus and during ontogeny

Abstract

Manganese superoxide dismutase (MnSOD) is an antioxidant enzyme usually located in mitochondria. There are only a few examples of cytosolic MnSOD (cMnSOD). In the shrimp Litopenaeus vannamei, we have previously characterized three cMnSOD cDNAs and their differential tissue-specific expression. To obtain insights about their genomic organization, we characterized the three corresponding cMnSOD genes, named them cMnsod1, cMnsod2, and cMnsod3 and studied their specific expression during ontogeny, response to lipopolysaccharides (LPS) and white spot virus infection (WSSV) in hemocytes from shrimp. The first two genes contain five introns flanked by canonical 5'-GT-AG-3' intron splice-site junctions, while the third one is intron-less. We analyzed 995 nucleotides upstream cMnsod2, but no classical promoter sequences were found. The deduced products of the three cMnSOD genes differ in two amino acids and there are four silent changes. cMnsod3 expression is modulated by WSSV and cMnsod2 by LPS. cMnsod2 is expressed from eggs to post larval stage during ontogeny. This is the first report of crustacean cMnSOD multigenes that are differently induced during the defense response and ontogeny.