title: Trypanosoma cruzi: cloning and characterization of two genes whose expression is up-regulated in metacyclic trypomastigotes.
abstract: The differentiation of epimastigotes into metacyclic trypomastigotes (metacyclogenesis) involves the transformation of a replicative non-infective form of Trypanosoma cruzi into a non-replicative infective stage. The study of genes with stage-specific expression may provide insight into the mechanisms involved in the regulation of gene expression in this parasite. We cloned and characterized two genes whose expression is up-regulated in metacyclic trypomastigote, those encoding metacyclin-II (Met-II) and metacyclin-III (Met-III). Nucleotide sequence analysis identified no sequence similarity with sequences available from genetic databases. The deduced amino acid sequences of the genes indicated that Met-III encodes a basic polypeptide whereas Met-II encodes an acidic polypeptide. Northern and Western blot analyses showed that Met-II and Met-III were expressed by metacyclic trypomastigotes, but not by epimastigotes. Antisera directed against the recombinant Met-II and Met-III proteins recognized two polypeptides on Western blots: a 16-kDa and a 24-kDa polypeptide. Immunocytochemistry analysis using electron microscopy showed that metacyclin-II is localized mainly at the kinetoplast whereas metacyclin-III is localized at the nucleus of the parasite. Southern blot analysis, using genomic DNA and T. cruzi chromosomes separated by pulsed-field gel electrophoresis, indicated that these genes were present as single copies on different chromosomes of T. cruzi Dm28c.
authors.affiliation: Departamento de Microbiologia, Universidade Estadual de Londrina, Paraná, Brazil.
authors.forename: Sueli Fumie
authors.initials: SF
authors.lastname: Yamada-Ogatta
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Motta
authors.forename: Helena Keiko
authors.initials: HK
authors.lastname: Toma
authors.forename: Viviane
authors.initials: V
authors.lastname: Monteiro-Goes
authors.forename: Andrea Rodrigues
authors.initials: AR
authors.lastname: Avila
authors.forename: Bruno Dallagiovana
authors.initials: BD
authors.lastname: Muniz
authors.forename: Celso
authors.initials: C
authors.lastname: Nakamura
authors.forename: Stenio Perdigão
authors.initials: SP
authors.lastname: Fragoso
authors.forename: Samuel
authors.initials: S
authors.lastname: Goldenberg
authors.forename: Marco Aurelio
authors.initials: MA
authors.lastname: Krieger
mesh_terms: D000818:Animals; D019976:Cloning, Organism / Q000379:methods*; D015870:Gene Expression / Q000235:genetics*; D017125:Genes, Protozoan / Q000235:genetics*; D008018:Life Cycle Stages / Q000235:genetics; D014349:Trypanosoma cruzi / Q000235:genetics*; D015854:Up-Regulation / Q000235:genetics