ANALYSIS OF EXPRESSED SEQUENCE TAGS (EST) OF Thalassophryne nattereri FISH VENOM GLANDS USING A cDNA LIBRARY CONSTRUCTED IN pGEM11ZF+

MAGALHÃES, G.S.(1), JUNQUEIRA DE AZEVEDO, I.M.J.(2), LOPES-FERREIRA, M.(1), HO, P.L.(2), MOURA-DA-SILVA, A.M.(1)

(1)Laboratório de Imunopatologia, Instituto Butantan, (2)Centro de Biotecnologia, Instituto Butantan, Brazil.

Envenomation by Thalassophryne nattereri fishes is an important medical problem in North and Northeast of Brazil, causing in human victims intense pain and edema followed by necrosis. The effects of T. nattereri venom in inflammation and blood coagulation include peculiar mechanisms, completely distinct from other animal venoms. These observations suggest that new categories of highly potent toxins might be present in this venom, and to assess this possibility a representative cDNA library obtained fromT. nattereri venom gland mRNA was used. The mRNA was extracted after gland stimulation by collecting its venom 4 days previously. Library was plated and 1,300 clones were isolated, of which a hundred have already been partially sequenced and searched for homology in the DDBJ/GENBANK with blastN and blastX programs. Clones matching known sequences were classified according to their function, showing similarity with proteins involved in cell structure/motility, gene/protein expression and metabolism. Some clones provided sequences showing low significant similarities with known gene products. Amongst this group, 4 sequences did not find any hit in the database, suggesting the presence of entirely new genes. Interesting enough 14 sequences showed similarity, yet low, with ADAM family of proteins, which are usually present in mammals and snake venoms representing important components for cell-matrix interactions. These data suggest that this library is representative of the venom gland constitution and further sequencing will lead us to isolate the clones coding for the components of this venom responsible for its toxicity.

Financial support: FAPESP

CORRESPONDENCE TO:

Geraldo Santana Magalhães, Rua Gaspar ColaçoVillela, 58, São Paulo, SP, CEP: 04437150, Brasil, Email: gsmaga@usp.br