Molecular diversity and evolution of cystine knot toxins of the tarantula Chilobrachys jingzhao

Abstract

Cystine knot toxins (CKTs) in spider venoms represent a rich source of novel ligands for varied ion channels. Here, we identified 95 novel putative CKT precursors by analyzing expressed sequence tags of the tarantula Chilobrachys jingzhao venom gland. Phylogenetics analyses revealed one orphan family and six families with sequence similarity to known toxins. To further investigate the relationships of their structures, functions and evolution, we assayed 10 representative toxins for their effect on ion channels, and performed structure model comparisons, evolution analysis and toxin distribution analysis. This study revealed two major types of CKTs: pore-blocking toxins and gating modifier toxins. A few blockers were observed with relatively high abundance and wide distribution, which may be a category of original toxins that block channels conserved in various preys with relatively high specificity. The gating modifier families contain advanced toxins, usually have many members and interact with diverse regulatory components of channels.

Chemical Punch Packed in Venoms Makes Centipedes Excellent Predators

“…Total RNA was extracted from the venom glands of 20 centipedes using TRIzol (Invitrogen), and this was used to prepare cDNA using a SMART TM PCR cDNA synthesis kit (Clontech). The first strand was synthesized by using the 3Ј SMART CDS Primer II A (5Ј-AAGCAGTGGTATCAACGCAGAGTACT (30) N Ϫ1 N-3Ј, where N ϭ A, C, G, or T and N Ϫ1 ϭ A, G, or C) and SMART II A oligonucleotide, (5Ј-AAGCAGTGGTATCAACGCAGAGTACGCGGG-3Ј). The 5Ј PCR primer II A (5Ј-AAGCAGTGGTATCAACGCAGAGT-3Ј) provided by the kit was used to synthesize the second strand using Advantage polymerase (Clontech).…”

Venom components from Citharischius crawshayi spider (Family Theraphosidae): exploring transcriptome, venomics, and function

“…Some mass fingerprinting and proteomic analyses have been reported from spider venoms: Pterinochilus murinus [6]; Loxosceles gaucho [7]; Lasiodora parahybana [8]; Chilobrachys jinzhao [9]; Ornithoctonus huwena [10] and the recent comparison of peptidomes of the theraphosid Coremiocnemis tropix, Selenocosmia crassipes, Selenotholus foelschei, Brachipelma albiceps, B. hamorri and the Australian funnel-web spider Hadronyche infesa [11]. Nevertheless, the number of transcriptome references is still limited to: Chilobrachys jingzhao [12,13]; Loxosceles laeta [14]; Ornithoctonus huwena [15]; Aphonopelma sp. [16] and Lycosa singoriensis [17].…”

Jingzhaotoxin-35, a novel gating-modifier toxin targeting both Nav1.5 and Kv2.1 channels

“…A group of toxins isolated from the venom of the Chinese tarantula Chilobrachys jingzhao have been characterized to act as gating modifiers of cardiac sodium channels and Kv2.1 channels (Chen et al, 2008). For instance, JZTX-I, -II, and -IV acted on cardiac sodium channels (Xiao et al, 2005;Wang et al, 2008aWang et al, , 2008b; JZTX-XIII targeted at Kv2.1 channels (Yuan et al, 2012); JZTX-III and -XI inhibited both cardiac sodium channels and Kv2.1 channels (Liao et al, 2006(Liao et al, , 2007a.…”