Identification and characterization of atypical 2-cysteine peroxiredoxins from mud crab Scylla paramamosain: The first evidence of two peroxiredoxin 5 genes in non-primate species and their involvement in immune defense against pathogen infection

Fish Shellfish Immunol. 2017 Oct:69:119-127. doi: 10.1016/j.fsi.2017.07.040. Epub 2017 Jul 22.

Abstract

Peroxiredoxin 5 (Prx5) belongs to a novel family of evolutionarily conserved antioxidant proteins that protect cells against various oxidative stresses. Generally, no more than one Prx5 transcript had been reported in non-primate species. In this study, two Prx5 genes (coined as SpPrx5-1 and SpPrx5-2) were firstly isolated from the mud crab, Scylla paramamosain, through RT-PCR and RACE methods. The open reading frame of SpPrx5-1 and SpPrx5-2 were 561 bp and 429 bp in length, encoding 186 and 142 amino acids polypeptide, respectively. Both the conserved signatures of peroxiredoxin catalytic center and Prx5-specific domain were identified in SpPrx5-1 and SpPrx5-2. Phylogenetic analysis indicated that both SpPrx5 clustered together with other animal Prx proteins and were classified into Prx5 subfamily. Tissue-specific expression analysis revealed that both SpPrx5-1 and SpPrx5-2 were ubiquitously expressed, highest in hepatopancreas, and showed remarkably similar transcription patterns. Quantitative RT-PCR analysis exhibited that both SpPrx5 genes changed dramatically in hepatopancreas, although showing different expression profiles, after virus-analog poly (I:C) or Vibrio alginolyticus challenge. The expression levels of both SpPrx5s were significantly enhanced in hepatopancreas after poly (I:C) stimulation, while SpPrx5-2 exhibited a more prompt response than SpPrx5-1. Nevertheless, the expression levels of both SpPrx5s were significantly reduced in hepatopancreas after Vibrio alginolyticus challenge in which SpPrx5-1 showed a more prompt response than SpPrx5-2. These results suggested the involvement of SpPrx5s in responses against viral and bacterial infections and further highlighted their functional importance in the immune system of Scylla paramamosain.

Keywords: Immune response; Peroxiredoxin 5 gene; Poly (I:C); Scylla paramamosain; Vibrio alginolyticus; mRNA expression profiles.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Arthropod Proteins / chemistry
  • Arthropod Proteins / genetics
  • Arthropod Proteins / immunology
  • Base Sequence
  • Brachyura / genetics*
  • Brachyura / immunology*
  • Immunity, Innate*
  • Peroxiredoxins / chemistry
  • Peroxiredoxins / genetics*
  • Peroxiredoxins / immunology*
  • Phylogeny
  • Poly I-C / pharmacology
  • Sequence Alignment
  • Vibrio alginolyticus / physiology

Substances

  • Arthropod Proteins
  • Peroxiredoxins
  • Poly I-C