Effects of the disruption of the HSP70-II gene on the growth, morphology, and virulence of Leishmania infantum promastigotes Authors Cristina Folgueira Center for Molecular Biology (CSIC-UAM), Autonomous University of Madrid, Cantoblanco Javier Carrión Center for Molecular Biology (CSIC-UAM), Autonomous University of Madrid, Cantoblanco Javier Moreno Biological Research Center (CSIC), Madrid Jose M. Saugar WHO Collaborating Centre for Leishmaniasis, National Centre for Microbiology (ISCIII), Majadahonda Carmen Cañavate WHO Collaborating Centre for Leishmaniasis, National Centre for Microbiology (ISCIII), Majadahonda Jose M. Requena Center for Molecular Biology (CSIC-UAM), Autonomous University of Madrid, Cantoblanco Keywords: Leishmania infantum, gene HSP70-II, gene deletion, infectivity, phenotypic alterations Abstract The 70-kDa heat shock protein (HSP70) is highly conserved among both prokaryotes and eukaryotes and plays essential roles in diverse cellular functions not only under stress but also under normal conditions. In the protozoan Leishmania infantum, the causative agent of visceral leishmaniasis, HSP70 is encoded by two HSP70 genes. Here, we describe the phenotypic alterations of HSP70-II-deficient (Deltahsp70-II) promastigotes. The absence of HSP70-II caused a major alteration in growth as the promastigotes reached stationary phase. In addition, aberrant forms were frequently observed in Deltahsp70-II mutant cultures. An accumulation of cells in the G2/M phase in cultures of the Deltahsp70-II mutant was determined by flow cytometry. Furthermore, Deltahsp70-II promastigotes showed a limited capacity of multiplication within macrophages, even though attachment to and uptake by macrophages did not differ significantly from the wild-type. Moreover, Deltahsp70-II was highly attenuated in BALB/c mouse experimental infections. In mutants re-expressing HSP70-II, the growth rate was restored, the normal morphology was recovered, and interactions with macrophages increased. However, promastigotes re-expressing HSP70-II did not recover their virulence. Overall, these data highlight the essential role played by HSP70-II expression in Leishmania virulence, pointing to this gene as a promising target for therapeutic interventions. Downloads PDF Published 2009-02-24 Issue Vol. 11 No. 2 (2008) Section Research Articles License Submission of a manuscript to International Microbiology implies: that the work described has not been published before, including publication in the World Wide Web (except in the form of an Abstract or as part of a published lecture, review, or thesis); that it is not under consideration for publication elsewhere; that all the coauthors have agreed to its publication. The corresponding author signs for and accepts responsability for releasing this material and will act on behalf of any and all coauthors regarding the editorial review and publication process.If an article is accepted for publication in International Microbiology, the authors (or other copyright holder) must transfer to the journal the right–not exclusive–to reproduce and distribute the article including reprints, translations, photographic reproductions, microform, electronic form (offline, online) or any other reproductions of similar nature. Nevertheless, all article in International Microbiology will be available on the Internet to any reader at no cost. The journal allows users to freely download, copy, print, distribute, search, and link to the full text of any article, provided the authorship and source of the published article is cited. The copyright owner's consent does not include copying for new works, or resale. In these cases, the specific written permission of International Microbiology must first be obtained.Authors are requested to create a link to the published article on the journal's website. The link must be accompanied by the following text: "The original publication is available on LINK at <http://www.im.microbios.org>. Please use the appropiate URL for the article in LINK. Articles disseminated via LINK are indexed, abstracted, and referenced by many abstracting and information services, bibliographic networks, subscription agencies, library networks, and consortia.
