Análisis estructural de los ARNts mitocondriales triptófano, tirosina y prolina de la tortuga marina Eretmochelys imbricata

Abstract

The hawksbill sea turtle, which lives in tropical and subtropical waters globally, is in a population decline due to the depredation of eggs, consumption of meat, use of shell and accidental fishing. It is cataloged in critical danger of extinction by the IUCN because its population size has been reduced mainly by anthropic actions. The mtDNA has been used as a molecular marker in evolutionary, phylogenetic and population genetics studies. The mtDNA contains 22 genes of tRNAs that have presented mutations in humans associated with more than 200 pathologies and their study is relevant to determine the population status of priority species. In order to identify and analyze the mutational consequences present in the tRNAPro, tRNATyr and tRNATrp of hawksbills, the 1D, 2D and 3D structures were studied in 17 nesting and foraging hawksbill turtles of the Colombian Caribbean. The genes were amplified by PCR and sequenced by the Sanger method. Of the 17 turtles analyzed in the present study, the turtle Ei5 presented 8 point mutations in the sequences in the three tRNAs evaluated. The other 16 turtles had 100% nucleotide homologies in the tRNAPro, tRNATyr and tRNATrp.In the individual Ei5 the ARNtPro gene presented the mutations 54insG, C56T and T69C. The tRNATyr gene presented the 31insG mutation and the tRNATrp gene the 17insA, 18insT, 19insT mutations in the D loop and 52insT in the variable region. The 2D structures of the genes studied were folded into a typical cloverleaf shape. The 3D structure of the three genes evaluated in the Ei5 turtle presented modifications in the traditional canonical structure. The length between the anticodon end and the CCA3 'end of the tRNATyr gene presented a distance lower than the minimum value of functionality (6.125 nm in 16 turtles) while in the tRNAPro and tRNATrp genes the distance is within the range of aminoacylation (7.5 -8.0 nm). However, at this distance it is necessary to add the length of the CCA sequence that is added to the tRNA in a post-transcriptional manner, generating a high probability of being functional. This work represents the first approach to the structural analysis of tRNA genes in hawksbill turtles in Colombia.