Estratégias de anotação do Transcriptoma do Télson de Tityus serrulatus

Abstract

The yellow scorpion, Tityus serrulatus is well adapted to the urban environment, with opportunistic behavior and parthenogenetic reproduction, qualities that make them hard to perform a population control. That is why scorpionism has surpassed in absolute numbers all the records of accidents with venomous animals in Brazil, including those with snakes and spiders. Between 2014 and 2016, about one person died every three days in Brazil, half of them children. Tityus serrulatus venom is the most aggressive among Brazilian scorpions. The detailed discovery of its components would aid public health measures, contributing to the production of a more specific and effective scorpion antivenom, with less adverse reactions. It would also assist in the development of products, with biotechnological and pharmaceutical potential and to provide an evolutionary view of this arachnid. Transcriptomy is a powerful field of study that helps in unveiling transcripts of certain tissues at a given time, under certain physiological conditions. A cDNA library from Tityus serrulatus telson was sequenced by RNA-Seq and an assembly was performed considering the program's default parameters. The assembly was evaluated for possible gene completeness, by calculating the presence of the orthologous genes described for arthropods. The result was 77.3%. Subsequently, the assembly was submitted to several annotation strategies. Searches for similarities, using BLAST2GO and BLAST®; searches for domains and protein motifs with support from INTERPRO; associations with GO terms by BLAST2GO and HMMER2GO and verification of involvement in metabolic pathways by the KAAS KEGG were performed. These techniques were complementary, increasing the number of contigs annotated and bringing more information about a portion of them. We annotated the totality of 73,35% of the chosen assembly and 72% of the proteins already described for T. serrulatus were found. There are already two other transcriptomic profiles of Tityus serrulatus telson described in the literature; however, different methodologies for mRNA extraction and cDNA sequencing were applied. This divergence is sufficient to reveal new molecules present in the venom of the scorpion, besides pointing out new ontological characterizations and metabolic pathways of the transcriptome. Several putative proteins, from other transcriptomic studies, which are believed to be produced by the venomous gland of T. serrulatus, were also found. This reinforces the relevance of experimental methods in the evaluation of those proteins, especially the ones with toxic activity.