Transferrin gene expression in Salmo sp. | Izražanje transferinskih genov pri postrvih (Salmo sp.)

English. 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.

Slovenian. Družina salmonidov združuje sladkovodne in anadromne vrste rib. Za salmonide je značilno, da imajo podvojene mnoge lokuse v genomski DNA, nekatere kot posledica tetraploidizacije genoma, druge kot posledica neodvisne podvojitve posameznih regij DNA. Pri rodu Salmo so dokazali podvojenost transferinskega gena pri atlantskem lososu, potočni in soški postrvi. Namen dela je bila karakterizacija promotorske regije obeh genov (TF1, TF2) pri vseh treh vrstah in določitev razmerja v izražanju TF1 in TF2 pri atlantskem lososu. S qPCR smo dokazali, da se pri atlantskem lososu TF2 izraža šestkrat šibkeje od TF1; predhodno je bilo dokazano, da je razlika v izražanju obeh genov pri potočni in soški postrvi še večja. Določili smo nukleotidno zaporedje različno dolgim promotorskim regijam obeh različic gena pri treh vrstah. V promotorski regiji smo našli mikrosatelit, ki se razlikuje v dolžini tako med vrstami kot med genoma, in štiri SNP, ki so opredeljevale TF1 in TF2. Pri atlantskem lososu smo določili zaporedje daljšega odseka promotorske regije. V promotorju gena za TF1 atlantskega lososa se nahaja minisatelit, ki obsega 37 bp dolg motiv s preko 20 ponovitvami, medtem ko pri TF2 minisatelita ni. Pri analizi potencialnih vezavnih mest smo pri vseh promotorskih regijah našli pomembne regije za izražanje transferinskega gena.