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Transcriptional Changes in the Hookworm, Ancylostoma caninum, during the Transition from a Free-Living to a Parasitic Larva

By Bennett J. D. Datu, Robin B. Gasser, Shivashankar H. Nagaraj, Eng K. Ong, Peter O'Donoghue, Russell McInnes, Shoba Ranganathan and Alex Loukas

Abstract

Hookworms are soil-transmitted nematodes that parasitize hundreds of millions of people in developing countries. Here we describe the genes expressed when hookworm larvae make the transition from a developmentally arrested free-living form to a tissue-penetrating parasitic stage. Ancylostoma caninum can be “tricked” into thinking it has penetrated host skin by incubating free-living larvae in host serum – this is called “activation”. To comprehensively identify genes involved in activation, we used suppressive subtractive hybridization to clone genes that were up- or down-regulated in activated larvae, with a particular focus on up-regulated genes. The subtracted genes, as well as randomly sequenced (non-subtracted) genes from public databases were then printed on a microarray to further explore differential expression. We compared predicted gene functions between activated hookworms and the free-living nematode, Caenorhabditis elegans, exiting developmental arrest (dauer), and found enormous differences in the types of genes expressed. Genes encoding secreted proteins involved in parasitism were over-represented in activated hookworms whereas genes involved in growth and development dominated in C. elegans exiting dauer. Our data implies that C. elegans dauer exit is not a reliable model for exit from developmental arrest of hookworm larvae. Many of these genes likely play critical roles in host-parasite interactions, and are therefore worthy of pursuit for vaccine and drug development

Topics: Research Article
Publisher: Public Library of Science
OAI identifier: oai:pubmedcentral.nih.gov:2217673
Provided by: PubMed Central
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