Transcriptome analysis of Loxosceles laeta (Araneae, Sicariidae) spider venomous gland using expressed sequence tags.
BACKGROUND
The bite of spiders belonging to the genus Loxosceles can induce a variety of clinical symptoms, including dermonecrosis, thrombosis, vascular leakage, haemolysis, and persistent inflammation. In order to examine the transcripts expressed in venom gland of Loxosceles laeta spider and to unveil the potential of its products on cellular structure and functional aspects, we generated 3,008 expressed sequence tags (ESTs) from a cDNA library.


RESULTS
All ESTs were clustered into 1,357 clusters, of which 16.4% of the total ESTs belong to recognized toxin-coding sequences, being the Sphingomyelinases D the most abundant transcript; 14.5% include "possible toxins", whose transcripts correspond to metalloproteinases, serinoproteinases, hyaluronidases, lipases, C-lectins, cystein peptidases and inhibitors. Thirty three percent of the ESTs are similar to cellular transcripts, being the major part represented by molecules involved in gene and protein expression, reflecting the specialization of this tissue for protein synthesis. In addition, a considerable number of sequences, 25%, has no significant similarity to any known sequence.


CONCLUSIONS
This study provides a first global view of the gene expression scenario of the venom gland of L. laeta described so far, indicating the molecular bases of its venom composition.
Laboratório de Imunoquímica, Instituto Butantan, Av. Prof. Vital Brazil, 1500, CEP 05503-900, São Paulo, SP, Brazil. mpedrosa@ufrnet.br
Matheus de F
Mde F
Fernandes-Pedrosa
Inácio de L M
Ide L
Junqueira-de-Azevedo
Rute M
RM
Gonçalves-de-Andrade
Leonardo S
LS
Kobashi
Diego D
DD
Almeida
Paulo L
PL
Ho
Denise V
DV
Tambourgi
D000595:Amino Acid Sequence; D000818:Animals; D020224:Expressed Sequence Tags; D005260:Female; D015870:Gene Expression; D020869:Gene Expression Profiling; D015723:Gene Library; D006801:Humans; D006821:Hyaluronoglucosaminidase / Q000235:genetics; D008969:Molecular Sequence Data; D010727:Phosphoric Diester Hydrolases / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D001098:Spider Bites; D013111:Spider Venoms / Q000235:genetics; D013112:Spiders / Q000235:genetics* / Q000472:pathogenicity / Q000502:physiology
D012333:RNA, Messenger; D013111:Spider Venoms; C055161:loxosceles venom; D010727:Phosphoric Diester Hydrolases; D006821:Hyaluronoglucosaminidase