Biomedical subjects

Chengcai An

Publications and source records attributed to Chengcai An.

5 recordsLinked to original sources

PubMed2007

Identification of a new AT-rich-element binding factor PsATF1 and its combined effect with PsGBF on the activation of PsCHS1 promoter.

Chaltone synthase (CHS) is a key speed-limiting enzyme in the phenylpropanoid pathway which plays an important role in plant defense response against pathogens. In the PsCHS1 promoter, there is an AT-rich element (ATRE) which is required for the maximal elicitor-mediated activation. However, the transcription activator of the ATRE and its regulation mechanism in pea keep unclear. In this paper, a new ATRE-binding factor was isolated from an elicitor-induced pea cDNA expression library and was designated as PsATF1. Electrophoretic mobility shift assay (EMSA) indicated the ATRE-specific binding activity of PsATF1. Beta-galactosidase assays in yeast cells suggested that PsATF1 possessed transcription-activating activity because PsATF1 activated the expression of the reporter gene even without the GAL4 activation domain (AD). The current study also examined the co-activation effects of PsATF1 with another transcription factor PsGBF on ATRE or PsCHS1 promoter through a transient expression system. The present work reports that PsATF1 acts as a complete transcription activator and first indicates that there are combined effects of PsATF1 with PsGBF on the activation of PsCHS1 promoter. These results provide theoretical basis to the plant defense gene expression mechanism regulated by multiple activators.

AT Rich Sequence↗

PubMed2006

Identification of a bHLH-type G-box binding factor and its regulation activity with G-box and Box I elements of the PsCHS1 promoter.

With the use of in vivo recombination theory, the screening time of yeast one-hybrid system was decreased in the present study. A basic helix-loop-helix (bHLH) protein PsGBF was successfully obtained from a glutathione (GSH)-induced pea cDNA library using the G-box cis-element of the PsCHS1 promoter as a bait. Electrophoretic mobility shift assay (EMSA) and beta-galactosidase assay results suggested that PsGBF possesses both G-box-specific binding and transcription-activating activities. The specific interaction of PsGBF with G-box was further confirmed by in vivo transient expression assays in tobacco. The current study examined the combination effect of G-box with Box I elements in the interaction with PsGBF or OsMYC. The results indicated that PsGBF bound with the G-box, but not the Box I element. Moreover, this combination effect of G-box and Box I only associated with PsGBF but not with other bHLH-type proteins such as OsMYC.

Acyltransferases↗

PubMed2006

A novel bacterium Saprospira sp. strain PdY3 forms bundles and lyses cyanobacteria.

A helical filamentous cyanobactericidal bacterium was isolated from Dianchi Lake, a eutrophic freshwater lake in Kunming City of the Yunnan Province in China using a special solid medium. This species was designated strain PdY3. This bacterium was identified as a novel Saprospira sp. on the basis of its morphological characteristics and 16S rDNA sequence. Strain PdY3 showed apparent group behavior on the solid medium, forming orderly, bundle-like group structures. These bundles moved as groups. Individuals in a bundle responded to the bundle as a whole. PdY3 also showed group behavior and formed a three-dimensional reticular structure when co-cultured with Anabaena in liquid media. This helical bacterium lysed cyanobacteria through direct contact and its group behavior greatly accelerated the cyanobactericidal process. Our experiments showed that PdY3 caused lysis of 64% of Anabaena cells within 1 day and that its cyanobactericidal range was broad. These results underscore potential application of Saprospira on the control of blooms of cyanobacteria. PdY3 group behavior might allow a more efficient capture of bacterial prey.

Anabaena↗

PubMed2005

SiteFinding-PCR: a simple and efficient PCR method for chromosome walking.

In this paper, we present a novel PCR method, termed SiteFinding-PCR, for gene or chromosome walking. The PCR was primed by a SiteFinder at a low temperature, and then the target molecules were amplified exponentially with gene-specific and SiteFinder primers, and screened out by another gene-specific primer and a vector primer. However, non-target molecules could not be amplified exponentially owing to the suppression effect of stem-loop structure and could not be screened out. This simple method proved to be efficient, reliable, inexpensive and time-saving, and may be suitable for the molecules for which gene-specific primers are available. More importantly, large DNA fragments can be obtained easily using this method. To demonstrate the feasibility and efficiency of SiteFinding-PCR, we employed this method to do chromosome walking and obtained 16 positive results from 17 samples.

Arabidopsis↗

PubMed2005

Expression and purification of Huwentoxin-I in baculovirus system.

Huwentoxin-I (HWTX-I) is a novel neurotoxin isolated from the venom of Orinithoctonus huwena. Based on its biological activity, HWTX-I could be developed as a pain-killer for clinical purpose. Production of HWTX-I by the bacterium or yeast expression systems resulted in poor yields and the purified protein was proved to have lower biological activity than that of native one. So, for the first time, we introduced a new method to express HWTX-I gene in Sf9 cells using baculovirus expression system. Recombinant HWTX-I was recognized by Western blotting and then purified by nickel-chelating affinity chromatography under native conditions. Recombinant HWTX-I showed identical amino acid sequence as native form and exhibited similar effect on muscular transmission with that of native form. These results indicate that the baculovirus expression system and native purification strategy are viable ways to produce active HWTX-I.

Animals↗