Dramatic expansion of the black widow toxin arsenal uncovered by multi-tissue transcriptomics and venom proteomics

Table 1 Summary of groups of toxins and enzymes in L. hesperus venom gland specific transcripts

Type	Number^a	% expression	Proteomic evidence	Proposed function
Latrodectins	2	16.1	Yes	Facilitate latrotoxin action
Latrotoxins	39 (20)	15.8	Yes	Form calcium channels, cause neurotransmitter release in target organism
Putative ICK	7	14.2	Yes	Potential ion channel action
CRISPs	2/3	8.4	Yes	Calcium channel blocker, smooth muscle paralysis
Metalloproteases	8/11	7.8	Yes	Tissue degradation/spreading factor
ICK toxins	4	5.4	Yes	Alter function of neuronal ion channels
Serine proteases	6/7	2.8	Yes	Tissue degradation/ spreading factor
Chitinases	1	1.6	Yes	Breakdown of arthropod exoskeleton
LRR proteins	8/9	0.82	Yes	Diverse/neural development
Hyaluronidases	2	0.5	Yes	Breakdown of extracellular matrix/spreading factor

^aThe number preceding the slash is the total number of sequences with a BLAST hit to the defined type, while the number after the slash indicates the total number of sequences in this group including additional sequences identified in clustering analysis, but without a top BLAST hit to this sequence type. The number in parentheses indicates the minimum number of putative distinct latrotoxin paralogs. The number of putative ICKs is shown in italic as it is not based on BLAST homology (see text).
For each type, the total number of sequences, % of total expression among all venom gland specific transcripts for all sequences of this type, the proteomic evidence for the presence of the type in venom and the proposed function are shown.

ISSN: 1471-2164