Genome-wide screening of the classical cadherin gene family and cadherin-1 expression response infected with streptococcus agalactiae in nile tilapia (oreochromis niloticus)

Highlights

• A total of 18 classical cadherin gene family members were identified from Nile tilapia Oreochromis niloticus.

• Classical cadherin genes of Nile tilapia are highly diverse in sequence and motif.

• Cadherin1 (Oncdh1) associated with pathogen invasion were discussed.

• The expression level of Oncdh1 showed a significant induction or downregulation comparing with the control group.

Abstract

Classical cadherin gene family relies on calcium ions in playing an important role in adhesion between cells. However, comprehensive studies to identify classical cadherin gene families in Nile tilapia (Oreochromis niloticus) have not been conducted. In this study, 18 classical gene family members were screened from Nile tilapia using various bioinformatics methods. These screened cadherins were randomly scattered across eight different linkage groups and shared a conserved LDRE motif. A phylogenetic tree was constructed to explore the evolution of classical cadherin members. The result showed that all classical cadherins were clustered together to form an independent subfamily. In addition, MEME analysis indicated that almost all the screened cadherins had similar motif arrangements. Also, neural-cadherin has up to eight closely adjacent tandem trisomy motif repeats. Finally, the sequence characteristics of cadherin-1 (Oncdh1) associated with pathogen invasion were discussed. The open reading frame of Oncdh1 was 2052 bp, encoding sequences of 683 amino acids with three conserved domains: cadherin repeat-like domain, cadherin prodomain, and cadherin tandem repeat domain. Real-time PCR experiments were carried out to detect the expression pattern of Oncdh1 in head kidney, brain, intestine, and spleen after Streptococcus agalactiae infection. The results showed a significant induction or downregulation of the expression level of Oncdh1 compared with the control group. Overall, the findings of this study might provide a reference for further research on the function of classical cadherin family of Nile tilapia in the future.