title: Cloning and characterization of a gene for the stage-specific 82-kDa surface antigen of metacyclic trypomastigotes of Trypanosoma cruzi.
abstract: We have cloned and sequenced a cDNA clone coding for a metacyclic trypomastigote-specific surface glycoprotein with a molecular mass of 82 kDa (MTS-gp82). By immunoblotting and immunoprecipitation, antibodies against the recombinant protein recognized an 82-kDa protein of metacyclic trypomastigotes, without any detectable reaction towards amastigotes, epimastigotes or tissue culture-derived trypomastigotes. The insert of the MTS-gp82 cDNA clone strongly hybridized with a single 2.2-kb metacyclic trypomastigote mRNA, suggesting that the steady-state levels of mRNAs for MTS-gp82 are developmentally regulated. MTS-gp82 is encoded by a multigene family whose members are distributed in several chromosomes. Sequence analysis revealed 40-56% identity at amino acid level between MTS-gp82 and members of Trypanosoma cruzi gp85/sialidase family (TSA-1, Tt34c1, SA85-1.1). MTS-gp82 showed several amino acid motifs that are characteristic of gp85/sialidase family, such as the Asp box (SxDxGxTW), the subterminal (VTVxNVFLYNR) motif and the putative GPI-anchor sequence. On the basis of its structural features, the MTS-gp82 gene could be included in the T. cruzi gp85/sialidase family, but constituting a distinct group which is preferentially expressed in metacyclic trypomastigotes.
authors.affiliation: Department of Microbiology, Immunology and Parasitology, Escola Paulista de Medicina, São Paulo, Brazil.
authors.forename: J E
authors.initials: JE
authors.lastname: Araya
authors.forename: M I
authors.initials: MI
authors.lastname: Cano
authors.forename: N
authors.initials: N
authors.lastname: Yoshida
authors.forename: J F
authors.initials: JF
authors.lastname: da Silveira
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000737:chemistry / Q000235:genetics*; D000954:Antigens, Surface / Q000737:chemistry / Q000235:genetics*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D016054:DNA, Protozoan / Q000235:genetics; D017125:Genes, Protozoan; D006023:Glycoproteins / Q000235:genetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D005810:Multigene Family; D009439:Neuraminidase / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016053:RNA, Protozoan / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014349:Trypanosoma cruzi / Q000235:genetics* / Q000254:growth & development / Q000276:immunology*; D014643:Variant Surface Glycoproteins, Trypanosoma
chemical_list: D000953:Antigens, Protozoan; D000954:Antigens, Surface; D018076:DNA, Complementary; D016054:DNA, Protozoan; D006023:Glycoproteins; D012333:RNA, Messenger; D016053:RNA, Protozoan; D014643:Variant Surface Glycoproteins, Trypanosoma; C070842:trypomastigote specific surface antigen; C069715:trans-sialidase; D009439:Neuraminidase