Gene sequence analysis of toxins from the spider Phoneutria nigriventer revealed an intronless feature

 

Ana Luiza Bittencourt Paiva1, Alessandra Matavel1 , Bruno César Souza Silva2 , Clara Guerra-Duarte1 , Marcelo Ribeiro Vasconcelos Diniz1

 

1 Diretoria de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias (FUNED), Belo Horizonte, MG, Brazil.

2 Universidade Federal de Minas Gerais (UFMG), Programa Interunidades de Pós-graduação em Bioinformática (ICB), Belo Horizonte, MG, Brazil.

 

Abstract

Background: Phoneutria nigriventer spider venom contains several cysteine-rich peptide toxins that act on different ion channels. Despite extensive studies on its venom and description of cDNA sequences of several of its toxin precursors, the gene structure of these toxins remains unknown.

 

Methods: Genomic regions encoding the precursors of three previously characterized P. nigriventer toxins – PnTx1, PnTx2-5 and PnTx4(5-5) – were amplified by PCR using specific primers. PCR fragments were cloned and sequenced. Obtained sequences were compared with their corresponding cDNA sequences.

 

Results: The size of PCR fragments obtained and sequences corresponding to genomic regions encoding for the toxin precursors matched their cDNA sequences.

 

Conclusions: Despite a few nucleotide substitutions in the genomic regions encoding for the toxin precursors when compared with cDNA sequences, the results of the present work indicate that P. nigriventer toxins do not contain introns in their genes sequences.

 

Keywords: Phoneutria Spider toxins Toxin genes

 

Correspondence: analuiza.paiva@funed.mg.gov.br

 

Received: 21 October 2019; Accepted: 18 March 2020; Published online: 30 April 2020