%0 Journal Article
%T Molecular Cloning and Sequence Analysis of the cDNAs Encoding Toxin-Like Peptides from the Venom Glands of Tarantula Grammostola rosea
%A Tadashi Kimura
%A Seigo Ono
%A Tai Kubo
%J International Journal of Peptides
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/731293
%X Tarantula venom glands produce a large variety of bioactive peptides. Here we present the identification of venom components obtained by sequencing clones isolated from a cDNA library prepared from the venom glands of the Chilean common tarantula, Grammostola rosea. The cDNA sequences of about 1500 clones out of 4000 clones were analyzed after selection using several criteria. Forty-eight novel toxin-like peptides (GTx1 to GTx7, and GTx-TCTP and GTx-CRISP) were predicted from the nucleotide sequences. Among these peptides, twenty-four toxins are ICK motif peptides, eleven peptides are MIT1-like peptides, and seven are ESTX-like peptides. Peptides similar to JZTX-64, aptotoxin, CRISP, or TCTP are also obtained. GTx3 series possess a cysteine framework that is conserved among vertebrate MIT1, Bv8, prokineticins, and invertebrate astakines. GTx-CRISP is the first CRISP-like protein identified from the arthropod venom. Real-time PCR revealed that the transcripts for TCTP-like peptide are expressed in both the pereopodal muscle and the venom gland. Furthermore, a unique peptide GTx7-1, whose signal and prepro sequences are essentially identical to those of HaTx1, was obtained. 1. Introduction Venoms are complex mixtures of many different components proven to be useful tools for biochemical, physiological, and pharmacological studies of ion channels and receptors. Toxins that recognize ion channel subgroups are versatile tools for channel studies and thus contribute to drug discovery [1, 2]. For example, a 25-amino-acid peptide isolated from the marine fish-hunting cone snail Conus magus, ¦Ø-conotoxin-MVIIA, blocks N-type voltage-dependent calcium channels. In 2004, ziconotide, the synthetic version of ¦Ø-conotoxin-MVIIA, was approved in the United States for the treatment of chronic severe pain refractory to other current pain medications. About 40000 different kinds of spiders are known at present. Spider venoms contain peptide neurotoxins and are expected to be a rich source of ion channel blockers [3¨C5]. Tarantulas, comprising more than 860 species, like all other spiders are predators that feed on a variety of vertebrate and invertebrate prey [6]. Tarantulas do not use webs for capture but are well-equipped predators, possessing a variety of venoms that target receptors in the nervous system, probably with adaptation to a certain type of prey [7, 8]. Tarantula venom has been suggested to contain 1000 or more peptide toxins [8]. Despite their diverse activities, these toxins display only a few widely conserved structural motifs that share remarkable
%U http://www.hindawi.com/journals/ijpep/2012/731293/