Construction and self-activation detection of yeast two-hybrid bait plasmid of human programmed cell death ligand 1 immunoglobulin variable region domain gene / 中国生物制品学杂志

@#Objective To construct a yeast two-hybrid recombinant bait plasmid of human programmed cell death ligand 1(PD-L1)immunoglobulin variable region(IgV)domain gene,detect its expression in yeast and detect the cytotoxicity and self-activation of PD-L1 IgV protein as well as the interaction between PD-L1 IgV and human thioredoxin(hTrx).Methods Human PD-L1 was analyzed by bioinformatics method,and primers were designed to amplify PD-L1 IgV domain based on the coding region of PD-L1 gene registered in NCBI GenBank database. PCR amplification was carried out with pENTERPD-L1 plasmid as template,and then cloned into yeast two-hybrid bait vector pGBKT7. The recombinant bait plasmid and pGBKT7 empty vector were transformed into Y2HGold yeast cells respectively,and the PD-L1 IgV gene and its expression were detected by PCR and Western blot;Meanwhile,the protein toxicity and self-activation of PD-L1 IgV were detected,and the interaction between PD-L1 IgV and hTrx was detected by drip plate method.Results The bioinformatics analysis results of PD-L1 were consistent with related reports. The recombinant bait plasmid pGBKT7-PD-L1 IgV was correctly constructed,and Y2HGold positive clone was obtained,in which PD-L1 IgV was stably expressed. The empty vector pGBKT7 and recombinant bait plasmid pGBKT7-PD-L1 IgV grew well on SD/-Trp and SD/-Trp/X-α-Gal plates with the same colony size and number and white colony,but they did not grow on SD/-Trp/X-α-Gal/AbA plates,which indicated that PD-L1 IgV protein had no toxicity and no self-activation effect on yeast. The results of drip plates test showed that all experimental groups grew well on SD/-Trp/-Leu plate,while only positive control group grew on SD/-Trp/-Leu/X-α-Gal/AbA plate and showed blue color,which indicated that bait protein PD-L1 IgV and hTrx did not self-activate,and there was no interaction between them.Conclusion Recombinant human PD-L1 IgV bait plasmid was successfully constructed. PD-L1 IgV protein showed no toxicity and self-activation effect on yeast cells,and there was no interaction between PD-L1 IgV and hTrx. Subsequently,hTrx can be used to construct a peptide aptamer library,from which peptide aptamers that specifically bind to PD-L1 IgV can be screened.

Identification of anti-Mycobacterium tuberculosis agents targeting the interaction of bacterial division proteins FtsZ and SepFe

Tuberculosis (TB) is one of the deadly diseases caused by Mycobacterium tuberculosis (Mtb), which presents a significant public health challenge. Treatment of TB relies on the combination of several anti-TB drugs to create shorter and safer regimens. Therefore, new anti-TB agents working by different mechanisms are urgently needed. FtsZ, a tubulin-like protein with GTPase activity, forms a dynamic Z-ring in cell division. Most of FtsZ inhibitors are designed to inhibit GTPase activity. In Mtb, the function of Z-ring is modulated by SepF, a FtsZ binding protein. The FtsZ/SepF interaction is essential for FtsZ bundling and localization at the site of division. Here, we established a yeast two-hybrid based screening system to identify inhibitors of FtsZ/SepF interaction in M. tuberculosis. Using this system, we found compound T0349 showing strong anti-Mtb activity but with low toxicity to other bacteria strains and mice. Moreover, we have demonstrated that T0349 binds specifically to SepF to block FtsZ/SepF interaction by GST pull-down, fluorescence polarization (FP), surface plasmon resonance (SPR) and CRISPRi knockdown assays. Furthermore, T0349 can inhibit bacterial cell division by inducing filamentation and abnormal septum. Our data demonstrated that FtsZ/SepF interaction is a promising anti-TB drug target for identifying agents with novel mechanisms.

Screening and verification of proteins of Salvia miltiorrhiza polyphenol oxidase interaction / 中国中药杂志

Polyphenol oxidase(PPO) is an important antioxidant enzyme in plants. It has the functions of scavenging active oxygen and synthesizing phenols, lignin, and plant protection factors, and can enhance the plant's resistance to stress and resistance to pests and diseases. Our previous research found that Salvia miltiorrhiza PPO gene can positively regulate salvianolic acid B synthesis. In order to further explore the mechanism, a pGBKT7-PPO bait vector was constructed using the cloned S. miltiorrhiza polyphenol oxidase gene(SmPPO, GenBank accession number: KF712274.1), and verified that it had no self-activation and no toxicity. The titer of S. miltiorrhiza cDNA library constructed by our laboratory was 4.75 × 107 cfu·mL~(-1), which met the requirements for library construction. Through yeast two-hybrid test, 22 proteins that could interact with SmPPO were screened. Only yeast PAL1 and TAT interacted with SmPPO through yeast co-transformation verification. Further verification was performed by bimolecular fluorescence complementary detection(BiFC). Only TAT and SmPPO interacted, so it meant that TAT and SmPPO interacted. TAT and SmPPO were truncated according to the domain, respectively. The first 126 amino acids of SmPPO and tyrosine amino transferase(TAT) were obtained to interact on the cell membrane and chloroplast. SmPPO was obtained by subcellular localization test, which was mainly loca-lized on the nucleus and cell membrane; TAT was localized on the cell membrane. Real-time quantitative PCR results showed that the SmPPO gene was mainly expressed in roots and stems; the TAT gene was expressed in roots, and the expression level in stems and flowers was low. This article lays a solid foundation for the in-depth study of the molecular mechanism of the interaction of S. miltiorrhiza SmPPO and TAT to regulate the synthesis of phenolic substances.

The STK domain of the cassava bacterial blight resistance protein RXam1 interacts with an E3 Ubiquitin Ligase / El dominio stk de la proteína de resistencia a la bacteriosis vascular de yuca rxam1 interactúa con una e3 ubiquitin ligasa

RESUMEN La yuca (Manihot esculenta) representa el pilar de la seguridad alimentaria para cerca de mil millones de personas, principalmente en las zonas tropicales. Uno de los factores limitantes de la producción de yuca es la bacteriosis vascular causada por la bacteria Xanthomonasaxonopodis pv. manihotis (Xam). Recientemente se identificó el gen RXaml el cual confiere resistencia parcial de yuca a cepas de Xam. RXaml codifica una proteína con un dominio LRR (Leucine Rich Repeats) extracelular y un dominio STK (Serina Treonina Kinasa) citoplasmático; estas proteínas son conocidas como RLKs (Receptor Like Kinases). En este estudio se realizó el tamizaje de una librería de ADNc de yuca mediante doble híbrido de levadura para identificar las posibles proteínas que interactúan con el dominio STK de RXam1. El tamizaje de 3x108 clones permitió identificar y confirmar cinco clones de ellos los cuales corresponden al mismo gen, el cual codifica para una proteína que presenta un dominio central de dedos de zinc CHY, seguido por un dominio C-terminal "RING finger" y un "Zinc ribbon" el cual fue denominado CRFE3-1 (Cassava RING Finger E3 ligase). La interacción entre STK y CRFE3-1 fue altamente especifica ya que se demostró también por doble híbrido que STK no interactúa con una E3 ligasa de Arabidopsis, altamente similar a CRFE3-1, así como tampoco CRFE3-1 interactúa con el dominio STK de un RLK de lechuga similar a RXam1. La identificación de CRFE3-1 sugiere que mecanismos de degradación proteica son importantes para regular la actividad de RXam1.

ABSTRACT Cassava (Manihot esculenta) represents food security support for nearly one billion people, mainly in the tropics. One of the limiting factors of cassava's production is cassava bacterial blight, caused by the bacterium Xanthomonas axonopodis pv. manihotis (Xam). Recently, the RXam1 gene was identified, which confers partial resistance to some Xam strains. RXam1 encodes a protein with an extracellular LRR (Leucine Rich Repeats) domain and a cytoplasmic STK (Serine Threonine Kinase) domain; these proteins are known as RLK (Receptor-like Kinases). In this study, a cassava cDNA library was screened using a yeast Two-hybrid assay to identify possible proteins interacting with the STK domain of RXam1. Screening of 3x108 clones allowed identifying and confirming five of them, which correspond to the same gene, and code for a protein that has a core domain of zinc fingers CHY, followed by a C-terminal "RING finger" domain and a "Zinc ribbon". This gene was called CRFE3-1 (Cassava RING Finger E3 ligase). It was also demonstrated by yeast Two-hybrid that STK does not interact with an E3 ligase of Arabidopsis that is highly like CRFE3-1. CRFE3-1 did not show interaction with the STK domain of an RLK of lettuce related to RXam1, indicating a highly specific interaction between cassava RXam1 STK and CRFE3-1. The identification of CRFE3-1 suggests that protein degradation mechanisms are important to regulate the activity of RXam1.

Construction of human promyelocytic cDNA library and its identification / 吉林大学学报(医学版)

Objective: To construct a cDNA library of human promyelocytic leukemia (HL60), and to elucidate the mechanism of related genes in the pathogenesis and development of acute promyelocytic leukemia (APL). Methods: The total RNA of HL60 cells was extracted by Trizol method. The mRNA of samples were isolated and purified by centrifugal column method. The first strand of the cDNA was synthesized by reverse transcriptase-polymerase chain reaction (RT-PCR) while the second strand was synthesized by enzyme-catalyzed method. The cDNA fragments were recovered and then linked to the pPR3-N vector. The human promyelocytic cDNA library was constructed by homologous recombination in yeast strain Y187. The culture fluid was coated with LB plate to identify the library capacity, and PCR method was used to identify the size and distribution of the inserted fragment. Results: The RNA strand extracted from HL60 cells was clear, non-degradable and had low dispersion. The purified cell mRNA was used as template to synthesize the cDNA. After recovering the cDNA fragments, the cDNA fragments were successfully linked to the pPR3-N vector. The recombinant vector was transformed into yeast strain Y187, and the human promyelocytic cDNA library was successfully constructed by homologous recombination. The original electro transformation bacteria were diluted 100 times and 10 μL coating plate was taken, about 250 clones were generated. The total library capacity was 2. 5 × 106 CFU mL-1 and the total library capacity was 1. 25 × 107 CFU for 5 mL of transformed original bacterial solution. The average insertion fragment was more than 1 200 bp, and the positive rate was 100%. Conclusion: The human promyelocyic cDNA library is successfully constructed, and it lays a foundation for studying the pathogenesis and therapeutic mechanism of leukemia.

Construction of Yeast Two-Hybrid Vectors for Screening Novel OTULIN-, OTUB1- and OTUB2-Interacting Protein from Human cDNA Library

@#Introduction: OTULIN, OTUB1 and OTUB2 are deubiquitinases, the enzymes responsible for reversing ubiquitination process that occupies key roles in numerous cellular processes. The ubiquitination protein-protein interaction (PPI) network has been extensively explored in order to unravel the complexity of ubiquitin pathway. However, many significant challenges remain to develop a network-based understanding of the ubiquitination complexity including incompleteness of human interactome. Therefore, we aim to construct a pair of yeast two-hybrid (Y2H) vectors using pDEST32/pDEST22 vector system as a preparation for screening OTULIN-, OTUB1- and OTUB2-interacting proteins from human cDNA library, with ultimate aim of expanding the PPI network in human ubiquitome. Methods: OTULIN, OTUB1 and OTUB2 were cloned into entry vector using pCR™8/GW/TOPO® TA Cloning® system and shuttled into pDEST™32 bait vector by LR recombination reaction. To generate Y2H prey library clones, cDNA library was synthesized from HEK293 cells and cloned into donor vector pDONR™222 before transferred into destination vector pDEST™22. Results: DNA sequencing analysis confirmed the correct sequence of OTULIN, OTUB1 and OTUB2 inserts in pDEST32. Meanwhile, generation of cDNA library in pDEST22 produced 5.2 x 106 clones. Randomly picked pDEST22-cDNA clones showed that the recombination rate was 83% and gel electrophoresis indicated that the inserts length ranged from 0.45 to 3.4 kb. Conclusion: OTULIN, OTUB1, OTUB2 and cDNA library were successfully cloned into Y2H bait and prey vectors. The clones have been transfected into competent yeast Saccharomyces cerevisiae strain MaV203 and Y2H experiment to screen novel OTULIN-, OTUB1- and OTUB2-interacting protein from human cDNA library is underway.

Interaction between wheat translationally controlled tumor protein TCTP and SNF1-related protein kinase SnRK1 / 生物工程学报

Translationally controlled tumor proteins (TCTP) and SNF1- related protein kinase (SnRK1) are conserved and widely present in eukaryotic cells. TCTP regulates cell division, plant growth and development, and mediates plant resistance against pathogen infection. SnRK1 participates in a range of physiological processes including sugar metabolism and resistance to abiotic and biotic stresses. Previous work in our laboratory demonstrated that wheat TCTP can respond to Puccinia triticina infection and induce host defense responses. In order to further investigate the mechanism of TaTCTP in wheat resistance to Puccinia triticina infection, we used TAP (tandem affinity purification) and mass spectrometry to screen the potential interactants of TaTCTP. A SNF1- related protein kinase (SnRK1) was identified as a potential interacting protein of TaTCTP. The results of yeast two-hybrid assay showed that TCTP could interact with SnRK1 in yeast, and the yeast carrying TCTP and SnRK1 could grow on SD/-Leu/-Trp/-His/-Ade (SD/-LWHA) medium. The fluorescence signal of the interaction between TCTP and SnRK1 was found to be distributed in the cytoplasm in the Bi-fluorescense complementation experiment. Co-IP experiments further showed that TCTP and SnRK1 could interact in plant cells. This study lays an important foundation for further studying the mechanism of TaTCTP in the interaction between wheat and Puccinia triticina, and it play a great influence on further improving the molecular mechanism of wheat resistant to Puccinia triticina.

Construction of yeast two-hybrid library of Salvia miltiorrhiza and screening of SmJAZ8 interaction protein / 中国中药杂志

The study is aimed to construct high quality Salvia miltiorrhiza cDNA library and obtain the SmJAZ8 gene of S. miltiorrhiza by yeast two-hybrid system. In this study， full-length cDNA was synthesized from roots， stems， leaves， flowers and hairy roots of S. miltiorrhiza. The full-length cDNA library was synthesized by SMART method and constructed with DSN homogenization technique. The results showed that the library capacity was 1.45×10⁶， the recombination rate was 100%， and the average size of the insert was 500-2 000 bp. The recombinant vector of pDEST-pGADT7-SmJAZ8 was constructed and transformed into Y2HGold strain. The interaction protein was screened by yeast two-hybrid system. The DnaJ protein and UBQ protein were screened by yeast two-hybrid system. This study has successfully constructed a full-length cDNA library of S. miltiorrhiza， and laid the foundation for the follow-up study on functional gene screening and gene function of S. miltiorrhiza.

Identification of anti-Gram-negative bacteria agents targeting the interaction between ribosomal proteins L12 and L10

Gram-negative bacteria have become the main pathogens and cause serious clinical problems with increased morbidity and mortality. However, the slow discovery of new antimicrobial agents is unable to meet the need for the treatment of bacterial infections caused by drug-resistant strains. The interaction of L12 and L10 is essential for ribosomal function and protein synthesis. In this study, a yeast two-hybrid system was established to successfully detect the interaction between L12 and L10 proteins from gram-negative bacteria , which allows us to screen compounds that specifically disrupt this interaction. With this system, we identified two compounds IMB-84 and IMB-87 that block L12-L10 interaction and show bactericidal activity against . We used glutathione--transferase (GST) pull-down and surface plasmon resonance (SPR) assays to demonstrate that these compounds disrupt L12-L10 interaction and the target of compounds was further confirmed by the overexpression of target proteins. Moreover, protein synthesis and elongation factor G-dependent GTPase activities are inhibited by two compounds. Therefore, we have identified two antibacterial agents that disrupt L12-L10 interaction by using yeast two-hybrid system.

Screening and verifying the proteins interacting with phosphorylation cluster of DNA-PKcs by yeast two-hybrid assay / 中华放射医学与防护杂志

Objective To screen and verify the proteins interacting with phosphorylation cluster of DNA dependent protein kinase catalytic subunit((DNA-PKcs) by yeast two-hybrid assay.Methods To know the proteins interacting with DNA-PKcs phosphorylation cluster,yeast two-hybrid assay was applied to screen the cDNA library of human hepatic tissue with a previously constructed plasmid pGBKT7-DPC.The positive clones were further identified by PCR,rotary validation and sequence analysis.Then the eukaryotic expression vectors of the bait protein and screened positive clone proteins were constructed and transfected into human embryonic kidney 293T cells to detect whether the proteins could been expressed correctly.At last,the bait protein and screened positive clone proteins were co-transfected into 293T cells and protein interaction was detected with Co-Immunoprecipitation (Co-IP) assay.Results After two rounds of screening using the yeast two-hybrid assay,12 candidate clones were obtained.Then 7 clones with different insert fragments were identified by PCR,and 3 positive proteins interacted with DNA-PKcs phosphorylation cluster were further verified by rotary validation.Sequencing analysis demonstrated that these 3 proteins were MBNL1,SIK2 and YY1AP1,respectively.Accordingly,the eukaryotic expression vectors of bait protein and 3 positive clone proteins were constructed successfully and expressed correctly in 293T ceils.Finally,the Co-IP assay confirmed that these 3 positive clone proteins could interact with DNA-PKcs phosphorylation cluster.Conclusions Proteins interacting with DNA-PKcs phosphorylation cluster are successfully screened and identified.

Screening and Analysis of Proteins Interacting with HCMV UL145 from a Human Fetal Brain cDNA Library / 中国医科大学学报

Objective To screen a human fetal brain cDNA library for proteins that can interact with HCMV UL145 using a yeast two-hybrid system.Methods A bait plasmid (pGBKT7-UL145) was constructed.Using HCMV UL145 as bait,a human fetal brain cDNA library was screened and proteins interacting with UL145 were identified using bioinformatic methods to sequence and analyze the positive clones.Results Three clones interacting with HCMV UL145 were found,and identified as FOXG1.Conclusion Several proteins interacting with HCMV UL145 in the human fetal brain cDNA library were identified as FOXG1,indicating that this protein may play an important role in the course of HCMV infection.

Screening of host proteins interacting with GP, VP30, NP,and L proteins of Ebola virus by yeast two-hybrid system / 军事医学

Objective To study the biological function of GP,VP30,NP and L proteins in Ebola virus(EBOV) infectious diseases,and to screen the host proteins which interact with GP,VP30,NP,and L proteins of EBOV from human liver cDNA library using yeast two-hybrid technique.Methods Recombinant PCR was used to construct bait plasmids pGBKT7-GP,pGBKT7-VP30,pGBKT7-NP and pGBKT7-L.Bait strains were combined with human liver cDNA library strains.The positive clones were analyzed by DNA sequencing and bioinformatics.A yeast recovery experiment was performed to further verify and exclude false positive results.Results We constructed bait plasmids pGBKT7-GP,pGBKT7-VP30,pGBKT7-NP and pGBKT7-L with the recombinant PCR method.Six host proteins which could interact with GP,VP30,NP,and L proteins were screened,including COMMD1,ALB,PSMD8,APOA2,CYP2E1,and HP.The yeast recovery experiment proved that COMMD1 and APOA2 might interact with NP protein.Conclusion A number of prey proteins which interact with GP,VP30,NP,and L proteins of EBOV are screened,which may provide reference for the research of EBOV.

Screening and identification of proteins interacting with HCMV UL132 protein / 吉林大学学报(医学版)

Objective:To screen the proteins interacting with the human cytomegalovirus(HCMV)UL132 protein from the human fetus brain cDNA library by using Yeast Two-Hybrid System, and to elucidate the possible mechanism of UL132 protein in congenital cytomegalovirus infection.Methods:The HCMV UL132 fragment was amplified by polymerase chain reaction,the amplified HCMV UL132 fragment and expression vector pGBKT7 were digested and purified,and the HCMV UL132 fragment was linked to the vector pGBKT7.The pGBKT7-UL132 was constructed and transformed to yeast AH109, then the Human Fetal Brain DNA Library DNA was transformed into AH109 yeast.Using HCMV UL132 as abait, a human fetus brain cDNA was screened and the proteins interacting with UL132 protein were searched, the positive clone was sequenced and analyzed by bioinformatics methods.Results:The bait expression vector pGBKT7-UL132 was successfully constructed.The results of double enzyme digestion showed that there were two visible bands of 800 and 7 000 bp, respectively.After transformation of library plasmid, the transformation efficiency was calculated, and the transformation efficiency was 6.6×103 cfu· μg-1.There were 95 blue clones by X-gal coloration reactionsequencing and there were 10 clones interacting with the protein encoded by UL141 protein.The BLAST analysis showed that 7 of them were highly homologous with CAML.Conclusion:CAML might be one interaction protein with HCMV UL132 in Human Fetus Brain cDNA Library,suggesting that the interaction may be associated with the invasion and proliferation of the HCMV.

Primary culture of cat intestinal epithelial cell and construction of its cDNA library / 中国血吸虫病防治杂志

Objective To establish the primary cat intestinal epithelial cells(IECs)culture methods and construct the cD-NA library for the following yeast two-hybrid experiment,so as to screen the virulence interaction factors among the final host. Methods The primary cat IECs were cultured by the tissue cultivation and combined digestion with collagenase XI and dispase I separately. Then the cat IECs cultured was identified with the morphological observation and cyto-keratin detection ,by using goat anti-cyto-keratin monoclonal antibodies. The mRNA of cat IECs was isolated and used as the template to synthesize the first strand cDNA by SMARTTM technology,and then the double-strand cDNAs were acquired by LD-PCR,which were subsequently cloned into the plasmid PGADT7-Rec to construct yeast two-hybrid cDNA library in the yeast strain Y187 by homologous recom-bination. Matchmaker?Insert Check PCR was used to detect the size distribution of cDNA fragments after the capacity calcula-tion of the cDNA library. Results The comparison of the two cultivation methods indicated that the combined digestion of colla-genase XI and dispase I was more effective than the tissue cultivation. The cat IECs system of continuous culture was established and the cat IECs with high purity were harvested for constructing the yeast two-hybrid cDNA library. The library contained 1.1× 106 independent clones. The titer was 2.8 × 109 cfu/ml. The size of inserted fragments was among 0.5-2.0 kb. Conclusion The yeast two-hybrid cDNA library of cat IECs meets the requirements of further screen research,and this study lays the foundation of screening the Toxoplasma gondii virulence interaction factors among the cDNA libraries of its final hosts.

Interaction between SPAG6 and TAC1 proteins / 中华男科学杂志

<p><b>Objective</b>To construct eukaryotic expression plasmids of the Tac1 gene and explore the interaction between TAC1 and sperm-associated antigen 6 (SPAG6).</p><p><b>METHODS</b>RNA was extracted from the heart, liver, spleen, lung, kidney, brain, muscle, and testis of 10 Kunming male mice and, after reverse transcription into cDNA, the expression of Tac1 in the above tissues was observed by RT-PCR. Tac1/pEGFP-N2 and Tac1/pGADT7 recombinant plasmids were constructed and Tac1/pEGFP-N2 was transfected into CHO and COS-1 cells, followed by localization and detection of the protein expression of TAC1 by immunofluorescence staining and Western blot. The interaction between TAC1 and SPAG6 was determined by yeast two-hybrid experiment and Western blot.</p><p><b>RESULTS</b>Tac1 was expressed mainly in the testis, brain and heart. The results of restriction enzyme digestion and sequencing indicated successful construction of the recombinant plasmids, with the restriction fragment length of 390 bp. TAC1 was localized in the whole body of the CHO cells when transfected alone, but expressed in the microtubule of the cells when cotransfected with SPAG6, with the molecular weight of 40 000. Yeast two-hybrid experiment showed the colonies of TAC1 and SPAG6 on the culture plate without Leu, Trp and His, both contained in the yeast fusion protein.</p><p><b>CONCLUSIONS</b>The Tac1 recombinant plasmid was constructed successfully and the interaction between TAC1 and SPAG6 was confirmed with the plasmid.</p>

Screening of candidate molecules interacting with protein kinase Wee1B from human ovary cDNA library and its regulation effect / 吉林大学学报(医学版)

Objective:To screen the new candidate molecules interacting with protein kinase Wee1B by yeast two hybrid system, and to analyze their interaction with Wee1B in the early stage of mouse fertilized eggs by bioinformatics.Methods:The plasmid pcDNA3.1/V5-His-TOPO-Wee1B wild type encoding mouse Wee1B gene was used as template to construct bait plasmid pGBKT7 Wee1B and the bait plasmid pGBKT7-Wee1B was transformed into yeast competent cells at SD/Trp (SDO),SD/Trp/X-α-Gal (SDO/X)and SD/Trp/X α Gal/AbA plates (SDO/X/A)plates to detect the toxicity and self-activation ability of yeast and its expression in yeast using Western blotting method.The yeast cells containing pGBKT7-Wee1B were fused with human ovary cDNA library, the yeast plasmid transformation of Escherichia coli positive clones were sequenced after identified by yeast transformation.BLAST analysis was carried out in GenBank,and its effect on the development of mouse fertilized eggs was deduced according to the gene annotation.Results:The double enzyme digestion analysis and sequencing analysis results showed that the pGBKT7-Wee1B bait plasmid was successfully constructed.The plasmid was transformed into the yeast,and there were no clones in the SDO/X/A plates.The pGBKT7-Wee1B and pGBKT7 empty vectors were transformed into the yeast,the bacteria were inoculated on the SDO plates,and the clones were uniformly grown on the two SDO plates.The positive clones were picked and expanded in culture,the protein was extracted and Western blotting showed that pGBKT7 Wee1B was expressed in the yeast.The bait plasmids were fused with human ovary cDNA library and the positive clones inserted into the fragment were identified by PCR. Nine proteins which interacted with Wee1B protein kinase were screened out by sequencing and blast analysis,and the proteins which could be closely related to the development of mouse oocytes and the development of fertilized eggs were analyzed by bioinformatics analysis.Conclusion:Using the yeast two hybrid system from human ovary cDNA library,nine interacting proteins with Wee1B protein kinase are screened and these screened proteins may regulate mouse oocyte maturation and early embryo development through interacting with Wee1B.

Porcine circovirus type 2 ORF4 protein binds heavy chain ferritin.

Porcine circovirus type 2 (PCV2) is the primary infectious agent of PCV-associated disease (PCVAD) in swine. ORF4 protein is a newly identified viral protein of PCV2 and is involved in virus-induced apoptosis. However, the molecular mechanisms of ORF4 protein regulation of apoptosis remain unclear, especially given there is no information regarding any cellular partners of the ORF4 protein. Here, we have utilized the yeast two-hybrid assay and identified four host proteins (FHC, SNRPN, COX8A and Lamin C) interacting with the ORF4 protein. Specially, FHC was chosen for further characterization due to its important role in apoptosis. GST pull-down, subcellular co-location and co-immunoprecipitation assays confirmed that the PCV2 ORF4 protein indeed interacted with the heavy-chain ferritin, which is an interesting clue that will allow us to determine the role of the ORF4 protein in apoptosis.

Screening of cellular proteins that interact with the classical swine fever virus non-structural protein 5A by yeast two-hybrid analysis.

Classical swine fever virus (CSFV), the pathogen of classical swine fever (CSF), causes severe hemorrhagic fever and vascular necrosis in domestic pigs and wild boar. A large number of evidence has proven that non-structural 5A (NS5A) is not only a very important part of viral replication complex, but also can regulate host cell’s function; however, the underlying mechanisms remain poorly understood. In the current study, aiming to find more clues in understanding the molecular mechanisms of CSFV NS5A’s function, the yeast two-hybrid (Y2H) system was adopted to screen for CSFV NS5A interactive proteins in the cDNA library of the swine umbilical vein endothelial cell (SUVEC). Alignment with the NCBI database revealed 16 interactive proteins: DDX5, PSMC3, NAV1, PHF5A, GNB2L1, CSDE1, HSPA8, BRMS1, PPP2R3C, AIP, TMED10, POLR1C, TMEM70, METAP2, CHORDC1 and COPS6. These proteins are mostly related to gene transcription, protein folding, protein degradation and metabolism. The interactions detected by the Y2H system should be considered as preliminary results. Since identifying novel pathways and host targets, which play essential roles during infection, may provide potential targets for therapeutic development. The finding of proteins obtained from the SUVEC cDNA library that interact with the CSFV NS5A protein provide valuable information for better understanding the interactions between this viral protein and the host target proteins.

Function analysis of outer membrane protein VirB4 in Brucella infecting embryo trophoblastic cells / 中国人兽共患病学报

Potential target proteins binding to VirB4 of type Ⅳ secretion system were screened during Brucella infected bovine embryonic trophoblast cells .Brucella VirB4 genes were amplified by PCR with species-specific primers .Expression vector pGBKT7-virB4 was constructed and analysed by sequencing and restriction enzymes ,transforming to the yeast strain Y187 and testing self-activation and toxicity .The cells model and cDNA library of bovine embryonic trophoblast cells infected with Brucella abortus strain were constructed respectively .Utilizing yeast two-hybrid system was employed to screen the target proteins of bovine embryo trophoblastic cells which was conjunctive with virB4 .These proteins were detected by real-time fluo-rescence quantitative PCR .The results suggested that bait plasmid pGBKT7-virB4 was successfully transformed into the Y187 and there was no toxicity and self-activation;the cDNA library of bovine embryonic trophoblast cells infected with Brucella abortus strain was constructed .There screened 13 positive plasmids in which Q10 and SLC3A2 were up-regulated at the mRNA level .In this paper ,we reported the interactions between the VirB4 protein of Brucella and the bovine embryo trophoblastic cells ,which provide an upstream work for further elucidating the pathogenesis of Brucella infection of the host cell .

LA PROTEÍNA PTHB DE Xanthomonas axonopodis pv. Manihotis ES AUTOACTIVA EN ENSAYOS DE DOBLE HÍBRIDO / The PthB Protein from Xanthomonas axonopodis pv. Manihotis is an Autoactive in Yeast Two-Hybrid Assays

La bacteriosis vascular de yuca producida por la bacteria Xanthomonas axonopodis pv. manihotis (Xam) es una enfermedad limitante para la producción de yuca. Dentro de los primeros factores de patogenicidad identificados en esta bacteria se encuentra el gen PthB. La proteína PthB pertenece a la familia de efectores PthA/AvrBs3, que se caracterizan por presentar dominios NLS (Nuclear Localization Signal) y un dominio AAD (Acidic Activation Domain), lo cual sugiere que estas proteínas actúan como factores de transcripción. La identificación de las proteínas de yuca que interactúan con PthB permitiría dar luces sobre la función de esta proteína en la patogenicidad de esta bacteria. En este trabajo se clonó PthB en una fusión traduccional con el BD (Binding Domain) del factor de transcripción GAL4. Después de transformar este constructo en una cepa de levadura, se observó autoactivación de los genes reporteros, incluso a concentraciones altas de 3-AT. La eliminación del primer, segundo o de los dos NLS y del AAD no eliminaron la capacidad de autoactivación de los genes reporteros mediada por PthB. Estos resultados indican la imposibilidad de su utilización en un tamizaje de una librería de ADNc de yuca para identificar las proteínas que interactúan con PthB.

Cassava bacterial blight disease is caused by the gram-negative bacteria Xanthomonas axonopodis pv. manihotis (Xam), and constitutes one of the most important constraints for cassava production. One of the first determinants of pathogenicity identified in this bacterium is the PthB gene. The PthB protein belongs to the PthA/AvrBs3 family, characterized by the presence of Nuclear Localization Signal (NLS) and Acidic Activation (AAD) domains, suggesting that these proteins are transcription factors. The identification of cassava proteins interacting with PthB could give insights about the function of this protein in the pathogenicity of this bacterium. In this work we cloned PthB in the yeast two hybrid expression vector pLAW10, generating a fusion protein with the Binding Domain (BD) of the transcription factor GAL4. In this work, PthB was cloned in a translational fusion with Gal4-BD (DNA Binding Domain). After transforming this construct into a yeast strain, autoactivation of the reporter genes was observed, even at the highest concentrations of 3-AT. The deletion of the first, second or both NLS and the AAD did not eliminate the ability of autoactivation of PthB. These results show the impossibility of using PthB to screen a cassava cDNA library to identify the proteins interacting with PthB.