Molecular cloning and characterization of the filarial LIM domain proteins AvL3-1 and OvL3-1
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1Division of Parasitology (Department of Zoology), Universität Hohenheim, Stuttgart, Germany.
Abstract:
A full-length cDNA of the filarial nematode Acanthocheilonema viteae was isolated from a cDNA library of female worms, using a partial cDNA of the OvL3-1 gene of Onchocerca volvulus as a probe. The AvL3-1 cDNA contained an open reading frame which encoded for a protein with a theoretical molecular weight of 64 kDa. The deduced protein contained a predicted signal sequence, a short repetitive motive of unknown function, and three LIM domains. The structure of the LIM domains was identical to those of zyxin, a cytoskeleton-associated protein of chicken fibroblasts, suggesting that AvL3-1 has a similar role in filarial nematodes. The sequence information was used to isolate the homologous cDNA of O. volvulus by PCR from a cDNA library of female O. volvulus, which showed an overall identity of 76.9% to AvL3-1 on the protein level. AvL3-1 was expressed in Escherichia coli and the affinity-purified fusion free protein was used to immunized jirds (Meriones unguiculatus). Immunization together with the adjuvant STP or with Freund's adjuvant induced IgG and IgM antibody responses, but no significant protection against a challenge infection with L3 of A. viteae, compared to appropriate control groups.
Insights
Researchers isolated the Acanthocheilonema viteae L3-1 (AvL3-1) gene, revealing a protein with LIM domains similar to zyxin. Immunization with AvL3-1 induced antibody responses but did not protect against filarial nematode infection.
Area of Science:
- Parasitology
- Molecular Biology
- Immunology
Background:
- Filarial nematodes cause significant human diseases.
- Understanding parasite proteins is crucial for developing control strategies.
Purpose of the Study:
- To isolate and characterize the AvL3-1 gene from Acanthocheilonema viteae.
- To investigate the potential of AvL3-1 as a vaccine candidate.
Main Methods:
- cDNA library screening using a probe from Onchocerca volvulus.
- Protein sequence analysis to identify functional domains.
- Polymerase Chain Reaction (PCR) for homologous gene isolation.
- Recombinant protein expression and purification.
- Animal immunization and challenge infection studies.
Main Results:
- A full-length cDNA encoding AvL3-1 (64 kDa) was isolated, featuring a signal sequence, repetitive motif, and three LIM domains similar to zyxin.
- Homologous cDNA from Onchocerca volvulus showed 76.9% protein identity to AvL3-1.
- Immunization of jirds with AvL3-1 induced IgG and IgM antibody responses.
- No significant protection against A. viteae challenge infection was observed.
Conclusions:
- AvL3-1 shares structural similarities with cytoskeleton-associated proteins, suggesting a potential role in nematode biology.
- While AvL3-1 elicits an immune response, it is not a protective antigen against A. viteae infection in this model.