title: Identification of the HSP70-II gene in Leishmania braziliensis HSP70 locus: genomic organization and UTRs characterization.
abstract: BACKGROUND
  The heat stress suffered by Leishmania sp during its digenetic life-cycle is a key trigger for its stage differentiation. In Leishmania subgenera two classes of HSP70 genes differing in their 3' UTR were described. Although the presence of HSP70-I genes was previously suggested in Leishmania (Viannia) braziliensis, HSP70-II genes had been reluctant to be uncovered.
  
  
  RESULTS
  Here, we report the existence of two types of HSP70 genes in L. braziliensis and the genomic organization of the HSP70 locus. RT-PCR experiments were used to map the untranslated regions (UTR) of both types of genes. The 3' UTR-II has a low sequence identity (55-57%) when compared with this region in other Leishmania species. In contrast, the 5' UTR, common to both types of genes, and the 3' UTR-I were found to be highly conserved among all Leishmania species (77-81%). Southern blot assays suggested that L. braziliensis HSP70 gene cluster may contain around 6 tandemly-repeated HSP70-I genes followed by one HSP70-II gene, located at chromosome 28. Northern blot analysis indicated that levels of both types of mRNAs are not affected by heat shock.
  
  
  CONCLUSIONS
  This study has led to establishing the composition and structure of the HSP70 locus of L. braziliensis, complementing the information available in the GeneDB genome database for this species. L. braziliensis HSP70 gene regulation does not seem to operate by mRNA stabilization as occurs in other Leishmania species.
authors.affiliation: Laboratorio de Parasitología Molecular, Departamento de Microbiología, Pontificia Universidad Javeriana, Carrera 7 No, 43-82, Edificio 52, Oficina 608, Bogotá, Colombia.
authors.forename: César A
authors.initials: CA
authors.lastname: Ramírez
authors.forename: José M
authors.initials: JM
authors.lastname: Requena
authors.forename: Concepción J
authors.initials: CJ
authors.lastname: Puerta
mesh_terms: D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; D000595:Amino Acid Sequence; D001483:Base Sequence; D005786:Gene Expression Regulation; D018503:Genome, Protozoan; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D007892:Leishmania braziliensis / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; D018840:HSP70 Heat-Shock Proteins; D015800:Protozoan Proteins