ABSTRACT
Objective To investigate the regulatory effects of cyclic diguanylate (c-di-GMP) signaling on CheB and CheR, which were chemotaxis regulatory proteins relating to the motility of Leptospira interrogans.Methods Real-time PCR was used to determine the expression of cheB1, cheB2, cheB3, cheR1 and cheR2 genes at mRNA level during Leptospira interrogans infection.Fragments of these genes were amplified and cloned into the expression vector pET-28a, respectively, to construct the prokaryotic expression system for them.Colony morphologies of Escherichia coli (E.coli) strains that overexpressed the target genes were observed to determine the regulatory effects of c-di-GMP on CheB and CheR.Results The expression of cheB1 gene at mRNA level increased 60 min after infection and reached the peak at 90 min.Compared with the control group, the expression of cheB3 gene at mRNA level were up-regulated, while no significant difference in the expression of cheB2 and cheR genes was observed 60 min after infection.The prokaryotic expression system for the five genes was successfully constructed and the purified proteins were obtained.CheB1, CheB3 and CheR2 improved the motility of E.coli, but that was inhibited by the inhibitor of diguanylate cyclase (DGC) or phosphodiesterase (PDE).Conclusion CheB and CheR regulate the swarming motility of E.coli and are affected by intracellular c-di-GMP.
ABSTRACT
AIM:To investigate the expression of transmembrane protein 16A(TMEM16A) in Fischer rat thy-roid follicular epithelial ( FRT) cells and its electrophysiologic properties .METHODS: The eukaryotic expression vector of pUB6/V5-TMEM16A was constructed and transfected into FRT cells by liposome-mediated transfection .In order to ob-tain the high efficiency of gene transfection and expression , the quantity and ratio of lipid/DNA complexes were optimized . The FRT cells stably expressing TMEM16A were gained by the selection with blasticidin and confirmed by the techniques of RT-PCR and immunofluorescence .The expression and location of TMEM 16A in the FRT cells were observed under an in-verted fluorescence microscope .TMEM16A protein was associated with calcium-dependent chloride current , as measured with halide-sensitive fluorescent protein and patch-clamp technique .RESULTS: The results of double digestion and se-quencing indicated that TMEM16A was cloned into pUB6/V5.The results of RT-PCR and immunofluorescence confirmed that TMEM16A was expressed in the FRT cells after transfection with TMEM16A.The classical calcium-activated chloride channel currents were recorded in the FRT cells stably expressing TMEM 16A by the technique of patch-clamp and halide-sensitive fluorescent protein YFP-H148Q/I152L.CONCLUSION:The protein expression of TMEM16A in the FRT cells was observed.TMEM16A is the molecular identity of calcium-activated chloride channels .