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

Sopwith, W. F., Debrabant, A., Yamage, M., Dwyer, D. M. and Bates, Paul (2002) 'Developmentally regulated expression of a cell surface class I nuclease in Leishmania mexicana'. International Journal for Parasitology, Vol 32, Issue 4, pp. 449-459.

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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 (Zn2+) 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. (C) 2002 Australian Society for parasitology Inc. Published by Elsevier Science Ltd. All rights reserved.

Item Type: Article
Subjects: QU Biochemistry > Enzymes > QU 135 Enzymes
QU Biochemistry > Cells and Genetics > QU 375 Cell physiology
QW Microbiology and Immunology > QW 52 Physiology and chemistry of microorganisms. Metabolism.
QX Parasitology > QX 45 Host-parasite relations
QX Parasitology > Protozoa > QX 70 Mastigophora. (e.g., Giardia. Trichomonas. Trypanosoma. Leishmania)
Faculty: Department: Groups (2002 - 2012) > Molecular & Biochemical Parasitology Group
Digital Object Identifer (DOI):
Depositing User: Users 494 not found.
Date Deposited: 21 Jan 2013 11:52
Last Modified: 17 Jul 2020 10:57


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