Bacterial two-hybrid system is a newly developed method for studying protein-protein interactions. However, in our studies of the interaction of regulatory proteins in Streptomyces, it was found that the bacterial two-hybrid system is not sensitive enough by the blue-and-white selection on X-gal plate. To overcome this drawback, the reason of false positive clone was firstly determined, which was the disturbance of other direct or indirect regulation on lacZ promoter. Then the disturbance was diluted by introducing multicopy lacZ promoter, which drive another reporter gene gfp. By such design, the sensitivity of the modified bacterial two-hybrid system was significantly inproved and the two different reporters also help to decrease the rate of the false positive clones. Further the evaluation of the modifiedd bacterial two-hybrid system indicated that the sensitivity was significantly improved.
Bacteria ; Genes, Reporter ; Promoter Regions, Genetic ; Protein Interaction Mapping ; methods ; Two-Hybrid System Techniques

Avian influenza virus Nucleoprotein (NP) is important in viral transcription, replication and determining host specificity of influenza virus. Yeast two-hybrid technique was applied to screen for proteins interacting with virus nucleoprotein, so as to further elucidate the interaction between virus nucleoprotein and cellular proteins, as well as the interaction between virus and host. To explore new proteins interacted with NP protein, a human brain cDNA library was screened using yeast two-hybrid system with NP as the bait. DNA inserts of the positive AD/library plasmids were sequenced. By the BLAST analysis against the GenBank databases seven positive clones resulted in seven genes. Our results could help for the further study on the molecular mechanism of virus replication, transcription and protein-protein interaction. Further investigations were needed to characterize these interactions.
Brain ; Gene Library ; Humans ; Influenzavirus A ; chemistry ; genetics ; Nucleoproteins ; metabolism ; Protein Binding ; Protein Interaction Domains and Motifs ; Protein Interaction Mapping ; Two-Hybrid System Techniques

OBJECTIVETo screen the protein interacting with retinoic acid receptor variant protein (RAR alpha-V) via the yeast two-hybrid technique (YTHT) and to find out the targets protein and study its biological function.

METHODSThe bait vector of pGBKT7-RAR alpha-V was constructed for screening proteins interacting with RAR alpha-V in K562 cell cDNA expression library via YTHT. The protein-protein interaction was confirmed with re-transformation in yeast and GST pull-down in vitro.

RESULTSThe bait vector was successfully constructed without toxicity, leakage and self-activation. Sixteen proteins were screened by YTHT and eight positive clones were identified by re-transformation in yeast. The interaction between RAR alpha-V and JTV-1 was confirmed by GST pull-down in vitro.

CONCLUSIONSThere are some kinds of proteins interacting with RAR alpha-V in cell. The biological dysfunction caused by certain protein-protein interaction may be involved in the pathogenesis of leukemia.

Gene Library ; Humans ; K562 Cells ; Protein Interaction Mapping ; Receptors, Retinoic Acid ; metabolism ; Retinoic Acid Receptor alpha ; Two-Hybrid System Techniques

OBJECTIVETo screen and identify the protein interacting with HBV antigen in hepatocytes. Then investigate the biological functions of hepatitis B virus antigen in the pathogenesis of hepatitis B and seek effective methods to prevent and treat it.

METHODSThe yeast two-hybrid system-3 technique was used to construct HBV PreS2, HBeAg, HBcAg, HBxAg bait plasmids. The bait plasmids transformed the yeast AH109 and expressed themselves in it. After being identified by SDS-PAGE and Western blot, the AH109 yeast was mated with yeast Y187 containing liver cDNA library plasmid in 2 x YPDA medium to form diploid yeast and was then plated on synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) and synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) containing x-alpha-gal for screening. Plasmids of blue colonies were extracted and transformed into Escherichia coli, then analyzed by DNA sequencing and bioinformatics. To further prove the interaction between HBV antigen and metallothionein, translation was performed by using reticulocyte lysate and coimmunoprecipitation was displayed in vitro.

RESULTSGenes coding for HBV antigen binding protein were successfully cloned and metallothionein was found in that protein. The interaction between HBeAg, HBcAg and HBxAg and metallothionein were further proved by coimmunoprecipitation in vitro.

CONCLUSIONThe interaction between HBV antigen and metallothionein indicates that metallothionein may participate in the pathogenesis of hepatitis B

Hepatitis B ; metabolism ; Hepatitis B Antigens ; chemistry ; Hepatocytes ; metabolism ; Humans ; Metallothionein ; chemistry ; Protein Interaction Mapping ; Two-Hybrid System Techniques

OBJECTIVETo screen proteins in hepatocytes interacting with HBeAg transactivated protein (HBeAgTP) with yeast-two hybrid technique for investigating the biological functions of HBeAgTP.

METHODSSuppression subtractive hybridization (SSH) and bioinformatics techniques were used for screening and cloning of the target genes transactivated by HBeAg. The HBeAgTP gene was amplified by polymerase chain reaction (PCR) and HBeAgTP bait plasmid was constructed with yeast-two hybrid system 3, and then transformed into yeast AH109. The transformed yeast mated with yeast Y187 containing liver cDNA library plasmid in 2 x YPDA medium. Diploid yeast was plated on synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) and synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) containing X-gal for selecting two times and screening. After extracting and sequencing of plasmid from blue colonies, the results were analyzed by bioinformatics.

RESULTSHBeAgTP gene was successfully cloned and expressed in yeast cells. Fifteen genes in twenty-four positive colonies were obtained using yeast-two hybrid technique.

CONCLUSIONHBeAgTP conjugated protein genes were successfully cloned, along with the genes involved in transcription and translation of proteins, immunoloregulation, materials and energy metabolism in vivo.

Hepatitis B e Antigens ; genetics ; metabolism ; Hepatitis B virus ; immunology ; Hepatocytes ; immunology ; metabolism ; Humans ; Protein Interaction Mapping ; Protein Precursors ; genetics ; metabolism ; Two-Hybrid System Techniques ; Yeasts ; genetics

OBJECTIVETo investigate the function of hepatitis B virus polymerase (HBV Pol) in the viral life cycle by screening the proteins interacting with HBV polymerase.

METHODSThe HBV Pol gene was constructed into the pGBKT7 vector. GAL4 yeast two-hybrid system was used to screen the human liver cDNA library to obtain proteins which interacted with HBV Pol. GST-pull down assay was applied to confirm the protein interactions.

RESULTSUbiquitously expressed transcript (UXT) was selected by the yeast two-hybrid system. GST-pull down assay confirmed the in vitro interaction between HBV Pol and UXT.

CONCLUSIONSUXT is a potential interactor of HBV Pol, and this protein interaction may provide clues of the function of HBV Pol in HBV life cycle.

Gene Products, pol ; metabolism ; Hepatitis B virus ; enzymology ; Humans ; Neoplasm Proteins ; metabolism ; Protein Interaction Mapping ; Two-Hybrid System Techniques ; Virus Replication

Atherosclerosis is a complex disease characterized by lipid accumulation in the vascular wall and influenced by multiple genetic and environmental factors. To understand the mechanisms of molecular regulation related to atherosclerosis better, a protein interaction network was constructed in the present study. Genes were collected in nucleotide database and interactions were downloaded from Biomolecular Object Network Database (BOND). The interactional data were imported into the software Cytoscape to construct the interaction network, and then the degree characteristics of the network were analyzed for Hub proteins. Statistical significance pathways and diseases were figured out by inputting Hub proteins to KOBAS2. 0. The complete pathway network related to atherosclerosis was constructed. The results identified a series of key genes related to atherosclerosis, which would be the potential promising drug targets for effective prevention.
Atherosclerosis ; genetics ; Databases, Factual ; Humans ; Protein Interaction Mapping ; methods ; Protein Interaction Maps ; Software

To screen the interactive proteins with IBDV Gt VP2 protein from cDNA library of B Lymphoid cells of the bursa of Fabricius. The expression cDNA library plasmids was transformed to the yeast competent cells, which have the bait plasmid-Gt VP2. After testing for growth in synthetic complete medium lacking histidine and uracil and for production of beta-galactosidase (X-gal), we obtained 16 positive clones. We searched the gene sequences of positive clones in the NCBI website. The blast results showed that five positive clones were the gallus sequences. They were Gallus gallus breed mitochondrial DNA, O_G1cNAc transferase, Tumor protein p53 binding protein, Stathmin and Chondroitin sulfate Ga1NAcT-2, respectively. This study is helpful for the further identifying the receptors of IBDV in B Lymphoid cells of the bursa of Fabricius.
Animals ; B-Lymphocytes ; metabolism ; virology ; Bursa of Fabricius ; metabolism ; Chickens ; DNA, Mitochondrial ; metabolism ; Gene Library ; Infectious bursal disease virus ; Protein Binding ; Protein Interaction Mapping ; Receptors, Virus ; metabolism ; Tumor Suppressor Protein p53 ; metabolism ; Two-Hybrid System Techniques ; Viral Structural Proteins ; genetics ; metabolism

Protein phosphatase-1 (PP1) nuclear targeting subunit (PNUTS), also called PP1R10, p99, or CAT 53 was originally isolated as a mammalian nuclear PP1-binding protein. In this study, we performed yeast two-hybrid screens to identify PNUTS-interacting proteins. Here, we report that LCP1 (epidermal Langerhans cell protein 1), a novel member of the HMG-box protein family, binds tightly to PNUTS. Co-immunoprecipitation of deletion constructs revealed that the C-terminus of LCP1 is sufficient for the interaction with an N-terminal region of PNUTS that is distinct from its PP1-binding domain. Furthermore, immunofluorescence studies showed that a subpopulation of LCP1 co-localizes with PNUTS in nuclear speckles. Importantly, we found that the N-terminus of LCP1 has a strong trans-activation activity in a GAL4-based heterologous transcription assay. The transcriptional activity of LCP1 is markedly suppressed by its interaction with PNUTS, in a PP1-independent manner. These findings suggest that the coordinated spatial and temporal regulation of LCP1 and PNUTS may be a novel mechanism to control the expression of genes that are critical for certain physiological and pathological processes.
Amino Acid Sequence ; Cell Line ; Cell Nucleus/*metabolism ; DNA-Binding Proteins/*metabolism ; HMGB Proteins/*metabolism ; Humans ; Molecular Sequence Data ; Nuclear Proteins/*metabolism ; Protein Binding ; Protein Interaction Mapping ; RNA-Binding Proteins/*metabolism ; Transcriptional Activation ; Two-Hybrid System Techniques

Animals ; Databases, Protein ; Humans ; Models, Molecular ; Protein Interaction Domains and Motifs ; Protein Interaction Mapping ; methods ; Protein Interaction Maps ; Proteins ; chemistry ; metabolism ; Proteome ; chemistry ; metabolism