Advances of structure and mechanisms of bromodomain-containing protein 4 and its related research in tumors / 生物工程学报

The bromodomain and extraterminal domain (Bet) family are the regulators of the epigenome and also the pivotal driving factors for the expression of tumor related genes that tumor cells depend on for survival and proliferation. Bromodomain-containing protein 4 (Brd4) is a member of the Bet protein family. Generally, Brd4 identifies acetylated histones and binds to the promoter or enhancer region of target genes to initiate and maintain expression of tumor related genes. Brd4 is closely related to the regulation of multiple transcription factors and chromatin modification and is involved in DNA damage repair and maintenance of telomere function, thus maintaining the survival of tumor cells. This review summarizes the structure and function of Brd4 protein and the application of its inhibitors in tumor research.

A Novel Polyclonal Antiserum against Toxoplasma gondii Sodium Hydrogen Exchanger 1

The sodium hydrogen exchanger 1 (NHE1), which functions in maintaining the ratio of Na+ and H+ ions, is widely distributed in cell plasma membranes. It plays a prominent role in pH balancing, cell proliferation, differentiation, adhesion, and migration. However, its exact subcellular location and biological functions in Toxoplasma gondii are largely unclear. In this study, we cloned the C-terminal sequence of T. gondii NHE1 (TgNHE1) incorporating the C-terminal peptide of NHE1 (C-NHE1) into the pGEX4T-1 expression plasmid. The peptide sequence was predicted to have good antigenicity based on the information obtained from an immune epitope database. After induction of heterologous gene expression with isopropyl-b-D-thiogalactoside, the recombinant C-NHE1 protein successfully expressed in a soluble form was purified by glutathione sepharose beads as an immunogen for production of a rabbit polyclonal antiserum. The specificity of this antiserum was confirmed by western blotting and immunofluorescence. The antiserum could reduce T. gondii invasion into host cells, indicated by the decreased TgNHE1 expression in T. gondii parasites that were pre-incubated with antiserum in the process of cell entry. Furthermore, the antiserum reduced the virulence of T. gondii parasites to host cells in vitro, possibly by blocking the release of Ca2+. In this regard, this antiserum has potential to be a valuable tool for further studies of TgNHE1.

Preparation and identification of anti-TgAQP peptide antibody / 中国人兽共患病学报

In this study ,we intended to prepare anti‐Toxoplasma gondii aquaporin (TgAQP) peptide antibody which was used to the application in the detection of the aquaporin expression and its subcellular localization of Toxop lasma gondii (T .gondii) ME49 strain .The B cell peptide antigen was designed based on the TgAQP amino acids sequence .After the pep‐tide antigen was conjugated to the KLH ,the fusion antigen was injected into New Zealand rabbits to prepare polyclonal anti‐body ,followed by identification of ELISA ,Western‐blotting and immunofluorescence assays .The ELISA showed that the titer of anti‐TgAQP antibody was about 1∶40 000 .Western blotting revealed the specific affinity of the antigen to polyclonal anti‐body at 29 .9 kDa protein T .gondii .The protein detected by the indirect immunofluorescence assays was distributed in the cy‐toplasm of the parasite .Thus far ,the anti‐TgAQP polyclonal antibody was successfully prepared ,providing a useful tool for further study of biological function and metabolic characteristics of TgAQP .

Preparation and identification of rabbit polyclonal antibodies against vacuolar proton pyrophosphatase type I of Toxoplasma gondii / 南方医科大学学报

<p><b>OBJECTIVE</b>To prepare and characterize rabbit polyclonal antibodies against Toxoplasma gondii vacuolar proton pyrophosphatase type I (TgVP1).</p><p><b>METHODS AND RESULTS</b>Two synthesized peptides TgVP1-1 and TgVP1-2 as the haptens were conjugated with KLH to immunize rabbits. Indirect ELISA showed that the titers of rabbit anti-TgVP1-1 polyclonal antibody and rabbit anti-TgVP1-2 polyclonal antibody reached 1:128 000. Western blotting results revealed that both purified polyclonal antibodies could specifically bind to a purified 85 kD T. gondii protein predicted as TgVP1. The protein detected by these two polyclonal antibodies was distributed in the cytoplasm of T. gondii tachyzoite, and this distribution pattern was consistent with that of acidocalcisome.</p><p><b>CONCLUSION</b>The peptide-based method of antibody generation is efficient and the obtained TgVP1 polyclonal antibodies possess a high specificity to facilitate further study of T. gondii acidocalcisome and the diagnosis of toxoplasmosis.</p>