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Developmentally regulated expression of a cell surface class I nuclease in Leishmania mexicana

Sopwith, William F and Debrabant, Alain and Yamage, Mat and Dwyer, Dennis M and Bates, Paul A (2002) Developmentally regulated expression of a cell surface class I nuclease in Leishmania mexicana. International journal for parasitology, 32 (4). pp. 449-459. ISSN 1879-0135

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Abstract

Leishmania mexicana, like other trypanosomatid parasites, is a purine auxotroph and must obtain these essential nutrients from its sandfly and mammalian hosts. A single copy gene encoding its unique externally oriented, surface membrane, purine salvage enzyme 3'-nucleotidase/nuclease, was isolated. Structural features of the deduced protein included: an endoplasmic reticulum-directed signal peptide, several conserved class I catalytic and metal co-factor (Zn(2+)) binding domains, transmembrane anchor sequence and a C-terminal cytoplasmic tail. 3'-Nucleotidase/nuclease gene (mRNA) and protein (enzyme activity) expression were examined in three different L. mexicana developmental forms: procyclic promastigotes, metacyclic promastigotes and amastigotes. Results of both approaches demonstrated that the 3'-nucleotidase/nuclease was a stage-specific enzyme, being expressed by promastigote forms (stages restricted to the insect vector), but not by amastigotes (which produce disease in mammalian hosts). Starvation of these parasites for purines resulted in the significant up-regulation of both 3'-nucleotidase/nuclease mRNA and enzyme activity in promastigotes, but not in amastigotes. These results underscore the critical role that the 3'-nucleotidase/nuclease must play in purine salvage during the rapid multiplicative expansion of the parasite population within its insect vector. To our knowledge, the L. mexicana 3'-nucleotidase/nuclease is the first example of a nutrient-induced and developmentally regulated enzyme in any parasitic protozoan.

Item Type: Article
Journal or Publication Title: International journal for parasitology
Uncontrolled Keywords: Leishmaniamexicana ; 3′-Nucleotidase ; Nuclease ; Purine salvage
Subjects: Q Science > QR Microbiology > QR355 Virology
Departments: Faculty of Health and Medicine > Biomedical & Life Sciences
ID Code: 56295
Deposited By: ep_importer_pure
Deposited On: 27 Jul 2012 15:05
Refereed?: Yes
Published?: Published
Last Modified: 27 Jul 2012 15:05
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/56295

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