Polycomb group proteins and their roles in regulating stem cell development / 中国医学科学院学报

Polycomb group (PcG) proteins are a family of epigenetic regulators responsible for the repression of genes in proliferation and differentiation of stem cells. PcG protein complex consists of two important epigenetic regulators: PRC1 (polycomb repressive complex 1) and PRC2 (polycomb repressive complex 2). In order to further understand the functions of PcG proteins in stem cell growth and differentiation, we review the PcG protein composition, PcG protein localization in the target gene, PcG protein recruitment, and the functions of PcG proteins in the development of stem cells.

Expression of anti-HBc single-chain variable fragment mediated by recombinant replication defective adenovirus in vitro / 中华肝脏病杂志

<p><b>OBJECTIVES</b>To define the expression of single-chain variable fragment (ScFv) against hepatitis B virus core protein (HBc) mediated by recombinant replication defective adenovirus carrying the anti-HBc ScFv gene in vitro and to define the activity of anti-HBc ScFv combining HBcAg.</p><p><b>METHODS</b>The recombinant adenoviruses carrying anti-HBc ScFv gene generated by homologous recombination in bacteria and packaged in 293 cells were transfected into HepG2 cells, and the anti-HBc ScFv was detected using SDS-PAGE and Western blot.</p><p><b>RESULTS</b>Green fluorescent protein (GFP) was observed in HepG2 cells after the transfection. SDS-PAGE displayed a protein strap about 2.7 x 10(4), and the result of Western blot displayed a positive reactive strap.</p><p><b>CONCLUSION</b>Anti-HBc ScFv can be expressed in cells mediated by recombinant replication defective adenovirus carrying the anti-HBc ScFv gene.</p>

The construction and characterization of human pro-urokinase mutant / 生物工程学报

It is very easy for the pro-UK to lose it's biological activity because of the digestion of pro-UK by the thrombin or the inhibition of pro-UK by the PAI-I. So three pro-UK mutant (pro-UK) genes were constructed in this experiment with the PCR point-mutant method. The thrombin cleavage site Arg156 in pro-UK was mutated into His156, and named as pro-UKM1; PAI binding sites Arg178, Arg179, Arg181 were mutated into Lys178, Lys179, His181, named as pro-UKM2; The mutant containing His156, Lys178, Lys179, His181 as pro-UKM3. Three mutants were expressed in CHO cells respectively and analyzed with SDS-PAGE fibrin plate assay and western blot. The results showed that the three mutants and the native pro-UK have the same single electrophoresis band indicating most of the pro-UK was single chain. In vitro plasma clot lysis assays indicated that the pro-UKM1 have the ability to resistant against thrombin digestion; pro-UK2 could resist against PAI inhibition; while pro-UK3 improved resistances against both thrombin and PAI. It looks very promising that the pro-UK3 can be a new medicine of dissolving thrombus.

Immune modulation of anti-HBV iRNA fromdifferent sources in patients with chronic hepatitis B / 中国临床药理学与治疗学

Aim To explore the function of immune modulation of anti-HBV iRNA in patients with chronic hepatitis B(CHB) Methods Peripheral blood lymphocyte iRNA was prepared from anti-HBs positive human body with HBV complete clearance after HBV infection(h-iRNA). The effect of h-iRNA on HBV specific lymphocyte proliferative response of peripheral lymphocyte from patients with CHB was observed by using MTT method and was compared with that by HBV specific iRNA from animal immunized only by HBsAg(a-iRNA).Results Both h-iRNA and a-iRNA increased the level of peripheral lymphocyte proliferative response to HBsAg in patients with CHB to some degree. In group of HBcAg, only h-iRNA showed its enhancement of HBcAg specific lymphocyte proliferative response.Conclusions h-iRNA can increase HBV specific lymphocyte proliferative response in patients with CHB and the function of increasing HBcAg specific lymphocyte proliterative response contributes to HBV clearance .