Dataset Information

Gene duplication in the genome of parasitic Giardia lamblia.

ABSTRACT:

Background

Giardia are a group of widespread intestinal protozoan parasites in a number of vertebrates. Much evidence from G. lamblia indicated they might be the most primitive extant eukaryotes. When and how such a group of the earliest branching unicellular eukaryotes developed the ability to successfully parasitize the latest branching higher eukaryotes (vertebrates) is an intriguing question. Gene duplication has long been thought to be the most common mechanism in the production of primary resources for the origin of evolutionary novelties. In order to parse the evolutionary trajectory of Giardia parasitic lifestyle, here we carried out a genome-wide analysis about gene duplication patterns in G. lamblia.

Results

Although genomic comparison showed that in G. lamblia the contents of many fundamental biologic pathways are simplified and the whole genome is very compact, in our study 40% of its genes were identified as duplicated genes. Evolutionary distance analyses of these duplicated genes indicated two rounds of large scale duplication events had occurred in G. lamblia genome. Functional annotation of them further showed that the majority of recent duplicated genes are VSPs (Variant-specific Surface Proteins), which are essential for the successful parasitic life of Giardia in hosts. Based on evolutionary comparison with their hosts, it was found that the rapid expansion of VSPs in G. lamblia is consistent with the evolutionary radiation of placental mammals.

Conclusions

Based on the genome-wide analysis of duplicated genes in G. lamblia, we found that gene duplication was essential for the origin and evolution of Giardia parasitic lifestyle. The recent expansion of VSPs uniquely occurring in G. lamblia is consistent with the increment of its hosts. Therefore we proposed a hypothesis that the increment of Giradia hosts might be the driving force for the rapid expansion of VSPs.

SUBMITTER: Sun J

PROVIDER: S-EPMC2829556 | biostudies-literature | 2010 Feb

REPOSITORIES: biostudies-literature

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Publications

Gene duplication in the genome of parasitic Giardia lamblia.

Sun Jun J Jiang Huifeng H Flores Roberto R Wen Jianfan J

BMC evolutionary biology 20100217

<h4>Background</h4>Giardia are a group of widespread intestinal protozoan parasites in a number of vertebrates. Much evidence from G. lamblia indicated they might be the most primitive extant eukaryotes. When and how such a group of the earliest branching unicellular eukaryotes developed the ability to successfully parasitize the latest branching higher eukaryotes (vertebrates) is an intriguing question. Gene duplication has long been thought to be the most common mechanism in the production of ...[more]

PMID: 20163721

Similar Datasets

Project description:Giardia lamblia is a parasitic protozoan that infects a wide range of vertebrate hosts including humans. Trophozoites are non-invasive but associate tightly with the enterocyte surface of the small intestine. This narrow ecological specialization entailed extensive morphological and functional adaptations during host-parasite co-evolution, including a distinctly polarized array of endocytic organelles termed peripheral vacuoles (PVs), which are confined to the dorsal cortical region exposed to the gut lumen and are in close proximity to the plasma membrane (PM). Here, we investigated the molecular consequences of these adaptations on the Giardia endocytic machinery and membrane coat complexes. Despite the absence of canonical clathrin coated vesicles in electron microscopy, Giardia possesses conserved PV-associated clathrin heavy chain (GlCHC), dynamin-related protein (GlDRP), and assembly polypeptide complex 2 (AP2) subunits, suggesting a novel function for GlCHC and its adaptors. We found that, in contrast to GFP-tagged AP2 subunits and DRP, CHC::GFP reporters have no detectable turnover in living cells, indicating fundamental differences in recruitment to the membrane and disassembly compared to previously characterized clathrin coats. Histochemical localization in electron tomography showed that these long-lived GlCHC assemblies localized at distinctive approximations between the plasma and PV membrane. A detailed protein interactome of GlCHC revealed all of the conserved factors in addition to novel or highly diverged proteins, including a putative clathrin light chain and lipid-binding proteins. Taken together, our data provide strong evidence for giardial CHC as a component of highly stable assemblies at PV-PM junctions that likely have a central role in organizing continuities between the PM and PV membranes for controlled sampling of the fluid environment. This suggests a novel function for CHC in Giardia and the extent of molecular remodeling of endocytosis in this species.

Dataset Information

Gene duplication in the genome of parasitic Giardia lamblia.

Background

Results

Conclusions

Publications

Gene duplication in the genome of parasitic Giardia lamblia.

Similar Datasets

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