title: Sequence analysis of the 3'-untranslated region of HSP70 (type I) genes in the genus Leishmania: its usefulness as a molecular marker for species identification.
abstract: BACKGROUND
  The Leishmaniases are a group of clinically diverse diseases caused by parasites of the genus Leishmania. To distinguish between species is crucial for correct diagnosis and prognosis as well as for treatment decisions. Recently, sequencing of the HSP70 coding region has been applied in phylogenetic studies and for identifying of Leishmania species with excellent results.
  
  
  METHODS
  In the present study, we analyzed the 3'-untranslated region (UTR) of Leishmania HSP70-type I gene from 24 strains representing eleven Leishmania species in the belief that this non-coding region would have a better discriminatory capacity for species typing than coding regions.
  
  
  RESULTS
  It was observed that there was a remarkable degree of sequence conservation in this region, even between species of the subgenus Leishmania and Viannia. In addition, the presence of many microsatellites was a common feature of the 3'-UTR of HSP70-I genes in the Leishmania genus. Finally, we constructed dendrograms based on global sequence alignments of the analyzed Leishmania species and strains, the results indicated that this particular region of HSP70 genes might be useful for species (or species complex) typing, improving for particular species the discrimination capacity of phylogenetic trees based on HSP70 coding sequences. Given the large size variation of the analyzed region between the Leishmania and Viannia subgenera, direct visualization of the PCR amplification product would allow discrimination between subgenera, and a HaeIII-PCR-RFLP analysis might be used for differentiating some species within each subgenera.
  
  
  CONCLUSIONS
  Sequence and phylogenetic analyses indicated that this region, which is readily amplified using a single pair of primers from both Old and New World Leishmania species, might be useful as a molecular marker for species discrimination.
authors.affiliation: Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autonoma de Madrid, 28049 Madrid, Spain. jmrequena@cbm.uam.es
authors.forename: Jose M
authors.initials: JM
authors.lastname: Requena
authors.forename: Carmen
authors.initials: C
authors.lastname: Chicharro
authors.forename: Lineth
authors.initials: L
authors.lastname: García
authors.forename: Rudy
authors.initials: R
authors.lastname: Parrado
authors.forename: Concepción J
authors.initials: CJ
authors.lastname: Puerta
authors.forename: Carmen
authors.initials: C
authors.lastname: Cañavate
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics*; D005786:Gene Expression Regulation / Q000502:physiology; D005819:Genetic Markers; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D007891:Leishmania / Q000235:genetics* / Q000378:metabolism*; D010802:Phylogeny; D013045:Species Specificity
chemical_list: D020413:3' Untranslated Regions; D005819:Genetic Markers; D018840:HSP70 Heat-Shock Proteins