Expression in Escherichia coli of the death domain of the human p55 tumor necrosis factor receptor

An efficient method for recombinant production of human alpha synuclein in Escherichia coli using thioredoxin as a fusion partner

Herein, we describe a simple and efficient approach to produce recombinant human α-synuclein (hAS) with high purity from Escherichia coli (E. coli). The cDNA for hAS was inserted into plasmid pET32a and expressed in E. coli BL21 (DE3) with an N-terminal tag containing E. coli thioredoxin (trx), followed by a histidine hexapeptide, and a tobacco etch virus (TEV) protease cleavage site (trx-6His-TEV). The fusion protein, trx-hAS, was initially released by osmotic shock treatment from the host cells and subsequently purified using a nickel affinity chromatography. A TEV protease cleavage step was performed to liberate the target protein, hAS, from the fusion partner, trx. Finally, an additional nickel affinity chromatography was performed to further purify the digested product. The yield of this method is ∼25 mg of tag-less protein (with ∼99% purity) per liter of culture volume. Reverse phase HPLC (RP-HPLC) and electrospray ionization (ESI) mass spectrometry confirmed the purity and authenticity of the purified protein. Thioflavin T (ThT) fluorescence assay, transmission electron microscopy (TEM), and circular dichroism (CD) spectroscopy demonstrated that the purified proteins form fibrils. Our protocol not only provides a convenient procedure for preparing highly pure hAS, but also requires very little specialized laboratory techniques.

Bladder cancer-associated protein is suppressed in human cervical tumors

Bladder cancer-associated protein (BLCAP) is downregulated in bladder cancer and has been identified as a prognostic biomarker for human bladder cancer. We previously reported that BLCAP mRNA is decreased in cervical cancer tissues, and overexpression of BLCAP was found to inhibit cell growth and induce apoptosis in the human cervical cancer HeLa cell line To investigate the BLCAP protein expression in cervical cancer and its potential clinical indications, we developed a polyclonal antibody against human BLCAP to assess the BLCAP protein expression in 30 cervical cancer tissues and 30 non-tumor cervical tissues from patients. Western blotting data showed that a single band of recombinant protein was probed by antiserum of BLCAP and no band was probed by pre-immune serum. BLCAP expression was significantly downregulated in cervical carcinoma tissues compared with its expression in the non-tumor cervical tissues. Moreover, cervical carcinoma tissues from patients with stage III-IV had significantly lower BLCAP expression percentage compared with stage I-II. Similarly, a significantly lower BLCAP expression percentage was observed in moderately/poorly differentiated tumor tissues and in the tumor tissues from patients with lymphatic metastasis (LM) compared with well-differentiated tumor tissues and non-LM patients, respectively. Our results suggest that decreased BLCAP protein expression is associated with poor prognosis and it could be a potential bio-index to predict cervical tumor patient outcome.