Transferrin gene expression in Salmo sp.

Abstract

Salmonidae family combines freshwater and anadromous fish species. Duplicates of numerous genomic DNA loci are characteristic for this family, some as a consequence of tetraploidisation, and others as independent doubling of discrete DNA regions. In the genus Salmo, duplication of transferrin gene in Atlantic salmon, brown and marble trout has been demonstrated. The aim of the study was to characterize the promoter region of both genes (TF1 and TF2) in all three species and to determine the ratio of expression of TF1 and TF2 in Atlantic salmon. Applying qPCR we showed that TF2 is expressed in Atlantic salmon six times weaker than TF1. It has been previously shown that the difference in the expression of both genes in brown and marble trout is even higher. The nucleotide sequence was determined for promoter regions of both genes in all species. In promoter region, microsatellite was found, which differs in length as well within species as between TF1 and TF2 locus, and four SNPs that differentiate TF1 and TF2. For Atlantic salmon, longer sequence of promoter region was determined. In TF1 gene, promoter contains a minisatellite, comprised of 37 bp long motif with over 20 replicates, while in TF2 minisatellite is not present. Analyzing potential binding sites in promoter region, functional elements for regulation of transferrin gene expression were found.

Keywords

• fish
• Atlantic salmon
• brown trout
• marble trout
• genetics
• transferrin genes