Molecular cloning of Gibel carp (<i>Carassius auratus gibelio</i>) complement component C3 and its expression profile after Cyprinid herpesvirus 2 infection

Abstract

The complement systems play an important role in innate and adaptive immunity. In this study, the complement C3 gene, designated CagC3, was cloned and sequenced from Gibel carp (Carassius auratus gibelio). The expression pattern of CagC3 in different tissues of healthy Gibel carp and after challenge with Cyprinid herpesvirus 2 (CyHV-2) were evaluated using quantitative real-time PCR. The full-length CagC3 cDNA was 5131 bp with an ORF of 4950 bp, encoding a predicted protein of 1649 amino acids. The deduced amino acid sequence showed that CagC3 has conserved domains and residues known to be critical for C3 function. Phylogenetic analysis demonstrated that CagC3 clustered with homologs from common carp and grass carp (Ctenopharyngodon idella). CagC3 is expressed in all examined tissues of healthy Gibel carp, with the highest expression in liver. In vivo, after CyHV-2 challenge, CagC3 transcription was significantly upregulated in liver, spleen and kidney with the peaks at 24 hr, 2 d, and 2 d, respectively. In vitro, CagC3 expression in the Gibel carp brain cell line showed the same pattern as that in vivo after stimulation with CyHV-2 or poly(I:C). However, CagC3 expression was downregulated at 24 hr after induction with lipopolysaccharide (LPS), and then reached the peak at 2 d. These results suggest that CagC3 is involved in the innate immune response of Gibel carp to viral infection.

Cyprinid herpesvirus‐2 (CyHV‐2): a comprehensive review

“…Fan et al . (2020) cloned and sequenced the complement C3 gene, designated CagC3, from Gibel carp and proved that CagC3 was involved in the innate immune response of Gibel carp to CyHV‐2 infection. Briefly, both innate and acquired immunity plays a crucial role in providing protection in goldfish against CyHV‐2 diseases and high water temperatures are reported to elicit better immune responses against CyHV‐2.…”

“…Lu et al (2019) reported that CyHV-2 miR-C12 suppresses virus-induced apoptosis and promotes virus replication by targeting caspase 8 and over-expression of miR-C12 reduces the expression of caspase 8 and inhibits CyHV-2 induced apoptosis. Fan et al (2020) cloned and sequenced the complement C3 gene, designated CagC3, from Gibel carp and proved that CagC3 was involved in the innate immune response of Gibel carp to CyHV-2 infection. Briefly, both innate and acquired immunity plays a crucial role in providing protection in goldfish against CyHV-2 diseases and high water temperatures are reported to elicit better immune responses against CyHV-2.…”

Transcriptomic Responses to Koi Herpesvirus in Isolated Blood Leukocytes from Infected Common Carp

“…However, the gene expression of c3 , a central component of the complement system, was not observed at mucosal sites, such as gills and skin [ 9 ]. Similarly, cyprinid herpesvirus 2 (CyHV2) infection in gibel carp ( Carassius auratus gibelio) induced the up-regulation of c3 transcription in internal organs but not at mucosal sites [ 85 ].The role of the complement system and autophagy in clearing KHV infection requires further research.…”

Seroconversion and Skin Mucosal Parameters during Koi Herpesvirus Shedding in Common Carp, Cyprinus carpio

“…C3 is a central component of the complement system and serves as a marker of both the classical, lectin, and alternative pathways. KHV infection in common carp, as well as Cyprinid Herpesvirus 2 (CyHV-2) infection in gibel carp ( Carassius auratus gibelio ), induced up-regulation of c3 transcription in internal organs (liver, spleen, and kidney) [ 51 , 52 ], but not at the mucosal site (gills) even though a strong up-regulation of bf/c2 transcripts, involved in the classical and alternative complement pathways, was observed [ 51 ]. Hence, the present study might suggest a subversion of the teleost complement system by KHV at the mucosal compartment during viral shedding, though the mechanisms involved in the host complement evasion are still to be elucidated.…”