Schistosoma mansoni venom allergen-like protein 18 (SmVAL18) is a plasminogen-binding protein secreted during the early stages of mammalian-host infection

Submitted by Ana Maria Fiscina Sampaio ([email protected]) on 2018-04-18T17:13:06Z No. of bitstreams: 1 Fernandes R Schistosoma mansoni venom allergen-like...pdf: 1525994 bytes, checksum: a5b5a8a1de73c2b0ded6e393837bc259 (MD5)Approved for entry into archive by Ana Maria Fiscina Sampaio ([email protected]) on 2018-04-18T17:23:51Z (GMT) No. of bitstreams: 1 Fernandes R Schistosoma mansoni venom allergen-like...pdf: 1525994 bytes, checksum: a5b5a8a1de73c2b0ded6e393837bc259 (MD5)Made available in DSpace on 2018-04-18T17:23:51Z (GMT). No. of bitstreams: 1 Fernandes R Schistosoma mansoni venom allergen-like...pdf: 1525994 bytes, checksum: a5b5a8a1de73c2b0ded6e393837bc259 (MD5) Previous issue date: 2018Fundação Butantan and Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP – 2012/23124-4 and FAPESP – 2010/18486-9).Instituto Butantan. Laboratorio de Desenvolvimento de Vacinas. São Paulo, SP, Brasil / Universidade de São Paulo. Pós-Graduação Interunidades em Biotecnologia. São Paulo, SP, BrasilInstituto Butantan. Laboratorio de Desenvolvimento de Vacinas. São Paulo, SP, Brasil / Universidade de São Paulo. Pós-Graduação Interunidades em Biotecnologia. São Paulo, SP, BrasilUniversidade de São Paulo. Instituto de Física de São Carlos. São Carlos, SP, BrasilInstituto Butantan. Laboratório de Parasitologia. São Paulo, SP, BrasilInstituto Butantan. Laboratório de Parasitologia. São Paulo, SP, BrasilFundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, BrasilInstituto Butantan. Laboratorio de Desenvolvimento de Vacinas. São Paulo, SP, BrasilInstituto Butantan. Laboratorio de Desenvolvimento de Vacinas. São Paulo, SP, BrasilSchistosomiasis is a neglected tropical disease caused by trematodes of the genus Schistosoma which have a complex life cycle characterized by an asexual multiplication phase in the snail intermediate host and a sexual reproduction phase in the mammalian definitive host. The initial steps of the human host infection involve the secretion of proteins contained in the acetabular glands of cercariae that promote parasite adhesion and proteolysis of the skin layers. Herein, we performed a functional analysis of SmVAL18, identified as one of the three SCP/TAPS proteins constituent of cercarial secretions. We evaluated the SmVAL18 binding to immobilized macromolecules of the extracellular matrix (ECM) and to plasma components. Recombinant protein, expressed in E. coli, was found to maintain an ordered secondary structure typical of the SCP/TAPS domain after purification. Expression of native SmVAL18 protein was verified to be restricted to cercariae and 3-h schistosomula stages; furthermore, the protein was observed in the corresponding secretions, confirming that SmVAL18 is secreted during the first 3 h of in vitro culture. rSmVAL18 was able to interact specifically with plasminogen (PLG) and enhance its conversion into plasmin in the presence of the urokinase-type plasminogen activator (uPA). Protein homology modelling suggested that the PLG-rSmVAL18 interaction was mediated by lysine residues of the protein. This was supported by in vitro data using the lysine analogue, 6-aminocaproic acid (ACA), which abolished the interaction. Finally, our results showed that both cercariae and 3-h schistosomula, as well as their corresponding secretions, exhibited the capacity to bind PLG and enhance its conversion into plasmin in vitro in the same way as observed for the recombinant protein. In conclusion, our findings show that SmVAL18 is a novel PLG-binding protein secreted during the early stages of the mammalian-host infection

Identification of human chromosome 22 transcribed sequences with ORF expressed sequence tags

Transcribed sequences in the human genome can be identified with confidence only by alignment with sequences derived from cDNAs synthesized from naturally occurring mRNAs. We constructed a set of 250,000 cDNAs that represent partial expressed gene sequences and that are biased toward the central coding regions of the resulting transcripts. They are termed ORF expressed sequence tags (ORESTES). The 250,000 ORESTES were assembled into 81,429 contigs. Of these, 1,181 (1.45%) were found to match sequences in chromosome 22 with at least one ORESTES contig for 162 (65.6%) of the 247 known genes, for 67 (44.6%) of the 150 related genes, and for 45 of the 148 (30.4%) EST-predicted genes on this chromosome. Using a set of stringent criteria to validate our sequences, we identified a further 219 previously unannotated transcribed sequences on chromosome 22. Of these, 171 were in fact also defined by EST or full length cDNA sequences available in GenBank but not utilized in the initial annotation of the first human chromosome sequence. Thus despite representing less than 15% of all expressed human sequences in the public databases at the time of the present analysis, ORESTES sequences defined 48 transcribed sequences on chromosome 22 not defined by other sequences. All of the transcribed sequences defined by ORESTES coincided with DNA regions predicted as encoding exons by genscan. (http://genes.mit.edu/GENSCAN.html)