The WD40-repeat proteins serve as a platform coordinating partner proteins and are involved in a range of regulatory cellular functions. A WD40-repeat protein (CsWD1) of Clonorchis sinensis previously cloned is expressed stage-specifically in the tegumental syncytium of C. sinensis metacercariae. In the present study, interacting proteins with the CsWD1 protein was purified by immunoprecipitation and 2 dimension gel electrophoresis from the C. sinensis metacercaria soluble extract, and tryptic peptides were analyzed by LC/ESI-MS. Putative partner proteins were annotated to be actin-2, glyceraldehyde-3-phosphate dehydrogenase, and hypothetical and unmanned proteins. The CsWD1 protein was predicted to contain 3 conserved actin-interacting residues on its functional surface. With these results, the CsWD1 protein is suggested to be an actin-interacting protein of C. sinensis.
Animals ; Antibodies, Helminth/metabolism ; Clonorchis sinensis/*physiology ; Electrophoresis, Gel, Two-Dimensional/veterinary ; Helminth Proteins/chemistry/*isolation & purification/metabolism ; Hydrogen-Ion Concentration ; Immunoglobulin G/chemistry ; Microfilament Proteins/chemistry/*isolation & purification/metabolism

OBJECTIVETo isolate and identify TRF1 immunoprecipitating protein complex and to clone the candidate gene.

METHODSThe co-immunoprecipitation assay was employed to isolate TRF1 protein complex and the immunoprecipitate was subjected to MALDI-TOF mass spectrometry for protein identification. The candidate gene was amplified by temperature-gradient PCR from human testis cDNA library and then cloned into pEGFP-C2 vector for eukaryotic expression. The amplified gene was verified by direct sequencing and GFP-tagged protein was confirmed by immunoblotting.

RESULTSTara protein with the size of 68 kD was identified from the TRF1 precipitate. The candidate gene amplified from cDNA library was about 1.7 kb as expected. Sequencing demonstrated the amplified fragment had 99.9% of homogenesis with Tara CDS sequence (gi:30474869). GFP-tagged fusion protein was about 100 kD. Tara was diffusely distributed in cytoplasm at interphase and in whole cells at mitotic phase.

CONCLUSIONTara might be an interacting protein with TRF1. However, further investigation would be required to confirm if they were bona fide partners.

Cloning, Molecular ; HeLa Cells ; Humans ; Microfilament Proteins ; genetics ; isolation & purification ; metabolism ; Protein Binding ; Telomeric Repeat Binding Protein 1 ; chemistry ; genetics ; metabolism