Molecular characterization and expression analysis of hepc1 and hepc2 in three tilapia species collected from Lake Manzala

Abstract

Background: Antimicrobial peptides were examined as an evolutionarily preserved component of the innate immune response and identified as a vital first-line defense against a broad spectrum of pathogens in fish. The objective of this study was to investigate the molecular characterization and expression analysis of hepc1 and hepc2 in three strains of tilapia species infected naturally in Lake Manzala. Results: The results revealed that the alignment of nucleotide sequences including cDNA and deduced amino acid sequences showed that hepcidin 1 in Sarotherodon galilaeus has four genotypes due to SNPs in codon 34Gln (CAG)/Leu (CTG) and codon 36Glu (GAA/GAG). Regarding hepcidin 2 gene, different genotypes were detected in Tilapia zillii and Sarotherodon galilaeus due to SNPs in codons 19Met (ATG)/Ile (ATT),57Pro (CCA)/Ser (TCA), and codon 14Leu (CTT / CTC). Hepcidins 1 and 2 coding region sequences in three tilapia species deposited to GeneBank and phylogenetic analysis indicated that tilapia species are more similar to each other and closely related to Sea perch. On the other hand, the expression levels of hepc1 and hepc2 genes were over-expressed in different tilapia tissue species (hepc1 in Sarotherodon galilaeus and hepc2 in Tilapia zillii). Conclusions: The results concluded that the hepcidin 1 and 2 genes showed constitutive expressions in most of tested tissues and have a very similar three-dimensional structure as well as mature peptides which mean that these genes are highly conserved within the species examined.