Screening of proteins binding to FXR1P using yeast two-hybrid technique / 南方医科大学学报

<p><b>OBJECTIVE</b>To screen the proteins interacting with FXR1P for functional investigation of FXR1P.</p><p><b>METHODS</b>The yeast strain AH109 transformed with the recombinant expression vector pGBKT7/FXR1 was mated with the yeast strain Y187 pretransformed with human fetal brain cDNA library. The positive clones were screened and identified by sequence analysis.</p><p><b>RESULTS</b>The recombinant expression vector pGBKT7/FXR1 was constructed successfully. Five proteins binding to FXR1P were screened from human fetal brain cDNA library using the yeast two-hybrid system, including CMAS, FTH1, GOLGA4, HSD17B1 and CSH1.</p><p><b>CONCLUSIONS</b>These results provide new clues for investigating the biological functions of FXR1P and the pathogenesis of Fragile X syndrome.</p>

Preparation and identification of monoclonal antibody against human thrombomodulin / 生理学报

To produce specific monoclonal antibody (McAb) against human thrombomodulin (hTM), the full-length hTM cDNA-expressing plasmid pThr402 was transfected into CHO cells by Lipofectamine 2000 reagent. The hTM-expressing CHO cells, which was confirmed by flow cytometry and Western blot, were obtained by G418 selection. Then the McAb against hTM was prepared with classic hybridoma technique. A cell line of CHO-TM5 with high level of hTM was used to immunize female Balb/c mice 3 times at an interval of 4 weeks. On the third day after the third immunization, mice were sacrificed and spleen cells were harvested to prepare hybridoma cells with SP2/0 cells at the ratio of 10 to 1. Hybridoma cells were then cultured at 96-well plates for screening. Cellular enzyme-linked immunoabsorbent assay (CELISA) was applied twice. The first CELISA was done with polythene ELISA plate with a monolayer of CHO-TM5 cells. The positive clones from the first screen were then selected by reacting with similar screening ELISA plate but with CHO cell monolayer instead. Only clones that were positive for the first screening and negative for the second screening were kept, and called as CHO-TM5(+)CHO(-) hybridoma cells. Balb/c mice were intraperitoneally injected with the selected hybridoma cells. Ascites were collected and monoclonal antibodies were purified using FPLC, and its Ig class, subclass, and titer were then determined respectively. The specificity of the yielded McAb was identified with CELISA, flow cytometry, ABC immunohistochemistry and immunoblotting. One line of hybridoma cells with high expression of specific McAb against hTM, NH-1, was obtained. The Ig subclass of the McAb was IgG1 and the titer of ascitic McAb was 1x10(-6). Flow cytometry, CELISA and Western blot assays demonstrated that McAb NH-1 could specifically recognize hTM expressed in CHO-TM5 cells and human umbilical vascular endothelial cells. Meanwhile, the tissue specificity of antigen recognized by McAb NH-1 was identified by immunohistochemical ABC staining. NH-1 can specifically recognize the natural hTM expressed mainly in vascular endothelial cells, which will potentially be useful for investigation of the functions and clinic values of hTM.