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Fulltext Cell-Based High-Throughput Screening Protocol for Discovering Antiviral Inhibitors Against SARS-COV-2 Main Protease (3CLpro)

Rothan HA, Teoh TC

Mol Biotechnol, 2021 Mar;63(3):240-248.
PMID: 33464543 DOI: 10.1007/s12033-021-00299-7

The global public health has been compromised since the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) emerged in late December 2019. There are no specific antiviral drugs available to combat SARS-CoV-2 infection. Besides the rapid dissemination of SARS-CoV-2, several variants have been identified with a potential epidemiologic and pathogenic variation. This fact has forced antiviral drug development strategies to stay innovative, including new drug discovery protocols, combining drugs, and establishing new drug classes. Thus, developing novel screening methods and direct-targeting viral enzymes could be an attractive strategy to combat SARS-CoV-2 infection. In this study, we designed, optimized, and validated a cell-based assay protocol for high-throughput screening (HTS) antiviral drug inhibitors against main viral protease (3CLpro). We applied the split-GFP complementation to develop GFP-split-3CLpro HTS system. The system consists of GFP-based reporters that become fluorescent upon cleavage by SARS-CoV-2 protease 3CLpro. We generated a stable GFP-split-3CLpro HTS system valid to screen large drug libraries for inhibitors to SARS-CoV-2 main protease in the bio-safety level 2 laboratory, providing real-time antiviral activity of the tested compounds. Using this assay, we identified a new class of viral protease inhibitors derived from quinazoline compounds that worth further in vitro and in vivo validation.

Matched MeSH terms: Recombinant Fusion Proteins/metabolism
Fulltext Characterisation of Drosophila Ubx CPTI000601 and hth CPTI000378 protein trap lines

Choo SW, Beh CY, Russell S, White R

ScientificWorldJournal, 2014;2014:191535.
PMID: 25389534 DOI: 10.1155/2014/191535

In Drosophila, protein trap strategies provide powerful approaches for the generation of tagged proteins expressed under endogenous control. Here, we describe expression and functional analysis to evaluate new Ubx and hth protein trap lines generated by the Cambridge Protein Trap project. Both protein traps exhibit spatial and temporal expression patterns consistent with the reported endogenous pattern in the embryo. In imaginal discs, Ubx-YFP is expressed throughout the haltere and 3rd leg imaginal discs, while Hth-YFP is expressed in the proximal regions of haltere and wing discs but not in the pouch region. The Ubx (CPTI000601) line is semilethal as a homozygote. No T3/A1 to T2 transformations were observed in the embryonic cuticle or the developing midgut. The homozygous survivors, however, exhibit a weak haltere phenotype with a few wing-like marginal bristles on the haltere capitellum. Although hth (CPTI000378) is completely lethal as a homozygote, the hth (CPTI000378) /hth (C1) genotype is viable. Using a hth deletion (Df(3R)BSC479) we show that hth (CPTI000378) /Df(3R)BSC479 adults are phenotypically normal. No transformations were observed in hth (CPTI000378), hth (CPTI000378) /hth (C1), or hth (CPTI000378) /Df(3R)BSC479 embryonic cuticles. We have successfully characterised the Ubx-YFP and Hth-YFP protein trap lines demonstrating that the tagged proteins show appropriate expression patterns and produce at least partially functional proteins.

Matched MeSH terms: Recombinant Fusion Proteins/metabolism
Chimeric Newcastle disease virus nucleocapsid with parts of viral hemagglutinin-neuraminidase and fusion proteins

Rabu A, Tan WS, Kho CL, Omar AR, Yusoff K

Acta Virol., 2002;46(4):211-7.
PMID: 12693857

The nucleocapsid (NP) protein of Newcastle disease virus (NDV) self-assembled in Escherichia coli as ring-like and herringbone-like particles. Several chimeric NP proteins were constructed in which the antigenic regions of the hemagglutinin-neuraminidase (HN) and fusion (F) proteins of NDV, myc epitope, and six histidines (a hexa-His tag) were linked to the C-terminus of the NP monomer. These chimeric proteins were expressed efficiently in soluble form in E. coli as detected by Western blot analysis. Electron microscopy of the purified products revealed that they self-assembled into ring-like particles. These chimeric particles exhibited antigenicity of the myc epitope, suggesting that the foreign sequences were exposed on the surface of the particles. Chickens inoculated with the chimeric particles mounted an immune response against NDV, suggesting the possibility of use of the ring-like particle as a carrier of immunogens in subunit vaccines and immunological reagents.

Matched MeSH terms: Recombinant Fusion Proteins/metabolism
Cloning and characterization of ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit (RbcS) cDNA from green microalga Ankistrodesmus convolutus

Thanh T, Chi VT, Abdullah MP, Omar H, Noroozi M, Napis S

Mol Biol Rep, 2011 Nov;38(8):5297-305.
PMID: 21287365 DOI: 10.1007/s11033-011-0679-4

An initial study on gene cloning and characterization of unicellular green microalga Ankistrodesmus convolutus was carried out to isolate and characterize the full-length cDNA of ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit (RbcS) as a first step towards elucidating the structure of A. convolutus RbcS gene. The full-length of A. convolutus RbcS cDNA (AcRbcS) contained 28 bp of 5' untranslated region (UTR), 225 bp of 3' non-coding region, and an open reading frame of 165 amino acids consisting of a chloroplast transit peptide with 24 amino acids and a mature protein of 141 amino acids. The amino acid sequence has high identity to those of other green algae RbcS genes. The AcRbcS contained a few conserved domains including protein kinase C phosphorylation site, tyrosine kinase phosphorylation site and N-myristoylation sites. The AcRbcS was successfully expressed in Escherichia coli and a ~21 kDa of anticipated protein band was observed on SDS-PAGE. From the phylogenetic analysis of RbcS protein sequences, it was found that the RbcS of A. convolutus has closer genetic relationship with green microalgae species compared to those of green seaweed and green macroalgae species. Southern hybridization analysis revealed that the AcRbcS is a member of a small multigene family comprising of two to six members in A. convolutus genome. Under different illumination conditions, RT-PCR analysis showed that AcRbcS transcription was reduced in the dark, and drastically recovered in the light condition. Results presented in this paper established a good foundation for further study on the photosynthetic process of A. convolutus and other green algae species where little information is known on Rubisco small subunit.

Matched MeSH terms: Recombinant Fusion Proteins/metabolism
Cloning, expression and display of the PreS domain of hepatitis B virus on filamentous bacteriophage M13

Kok WL, Yusoff K, Nathan S, Tan WS

J. Biochem. Mol. Biol. Biophys., 2002 Feb;6(1):55-8.
PMID: 12186783

The PreS domain of hepatitis B virus (HBV) is believed to be involved in virion assembly and attachment to a hepatocyte receptor during infection. In order to study the functions of this region, we fused it to the g3p protein of bacteriophage M13 that allows the fusion protein to be displayed at the tip of the filament. The fusion protein was detected by the anti-E tag antibody on a Western blot. The polypeptide in a soluble form was produced by transfecting a non-suppressor E. coli host cell with the recombinant phagemid. The soluble protein was detected in cytoplasm, in the periplasmic space and also in the medium. The functional display of the PreS domain would provide an alternative means to study its interactions with the nuleocapsid and hepatocytes.

Matched MeSH terms: Recombinant Fusion Proteins/metabolism
Fulltext Deciphering critical amino acid residues to modify and enhance the binding affinity of ankyrin scaffold specific to capsid protein of human immunodeficiency virus type 1

Saoin S, Wisitponchai T, Intachai K, Chupradit K, Moonmuang S, Nangola S, et al.

Asian Pac J Allergy Immunol, 2018 06;36(2):126-135.
PMID: 28802032 DOI: 10.12932/AP-280217-0037

BACKGROUND: AnkGAG1D4 is an artificial ankyrin repeat protein which recognizes the capsid protein (CA) of the human immunodeficiency virus type 1 (HIV-1) and exhibits the intracellular antiviral activity on the viral assembly process. Improving the binding affinity of AnkGAG1D4 would potentially enhance the AnkGAG1D4-mediated antiviral activity.
OBJECTIVE: To augment the affinity of AnkGAG1D4 scaffold towards its CA target, through computational predictions and experimental designs.
METHOD: Three dimensional structure of the binary complex formed by AnkGAG1D4 docked to the CA was used as a model for van der Waals (vdW) binding energy calculation. The results generated a simple guideline to select the amino acids for modifications. Following the predictions, modified AnkGAG1D4 proteins were produced and further evaluated for their CA-binding activity, using ELISA-modified method and bio-layer interferometry (BLI).
RESULTS: Tyrosine at position 56 (Y56) in AnkGAG1D4 was experimentally identified as the most critical residue for CA binding. Rational substitutions of this residue diminished the binding affinity. However, vdW calculation preconized to substitute serine for tyrosine at position 45. Remarkably, the affinity for the viral CA was significantly enhanced in AnkGAG1D4-S45Y mutant, with no alteration of the target specificity.
CONCLUSIONS: The S-to-Y mutation at position 45, based on the prediction of interacting amino acids and on vdW binding energy calculation, resulted in a significant enhancement of the affinity of AnkGAG1D4 ankyrin for its CA target. AnkGAG1D4-S45Y mutant represented the starting point for further construction of variants with even higher affinity towards the viral CA, and higher therapeutic potential in the future.

Matched MeSH terms: Recombinant Fusion Proteins/metabolism
Fulltext Delivery of chimeric hepatitis B core particles into liver cells

Lee KW, Tey BT, Ho KL, Tan WS

J Appl Microbiol, 2012 Jan;112(1):119-31.
PMID: 21992228 DOI: 10.1111/j.1365-2672.2011.05176.x

To display a liver-specific ligand on the hepatitis B virus core particles for cell-targeting delivery.

Matched MeSH terms: Recombinant Fusion Proteins/metabolism*
Dengue virus type 2 NS3 protease and NS2B-NS3 protease precursor induce apoptosis

Shafee N, AbuBakar S

J Gen Virol, 2003 Aug;84(Pt 8):2191-2195.
PMID: 12867651 DOI: 10.1099/vir.0.19022-0

Apoptosis was detected in Vero cell cultures expressing transfected dengue virus type 2 (DENV-2) genes. Approximately 17.5 and 51.5 % of cells expressing NS3 serine protease and NS2B-NS3(185) serine protease precursor protein [NS2B-NS3(185)(pro)] genes, respectively, were apoptotic. The percentage of apoptotic cells was significantly higher in cell cultures expressing NS2B-NS3(185)(pro). NS2B-NS3(185)(pro) was detected as NS2B-NS3(185)(pro)-EGFP fusion protein in cytoplasmic vesicular structures in the apoptotic cells. Site-directed mutagenesis which replaced His(51) with Ala within the protease catalytic triad significantly reduced the ability of the expressed NS3 and NS2B-NS3(185)(pro) to induce apoptosis. Results from the present study showed that DENV-2-encoded NS3 serine protease induces apoptosis, which is enhanced in cells expressing its precursor, NS2B-NS3(185)(pro). These findings suggest the importance of NS2B as a cofactor to NS3 protease-induced apoptosis.

Matched MeSH terms: Recombinant Fusion Proteins/metabolism
Fulltext Dengue virus type 2 envelope protein displayed as recombinant phage attachment protein reveals potential cell binding sites

Abd-Jamil J, Cheah CY, AbuBakar S

Protein Eng. Des. Sel., 2008 Oct;21(10):605-11.
PMID: 18669522 DOI: 10.1093/protein/gzn041

A method to map the specific site on dengue virus envelope protein (E) that interacts with cells and a neutralizing antibody is developed using serially truncated dengue virus type 2 (DENV-2) E displayed on M13 phages as recombinant E-g3p fusion proteins. Recombinant phages displaying the truncated E consisting of amino acids 297-423 (EB2) and amino acids 379-423 (EB4) were neutralized by DENV-2 patient sera and the DENV-2 E-specific 3H5-1 monoclonal antibodies suggesting that the phages retained the DENV-2 E antigenic properties. The EB4 followed by EB2 recombinant phages bound the most to human monocytes (THP-1), African green monkey kidney (Vero) cells, mosquito (C6/36) cells, ScFv specific against E and C6/36 cell proteins. Two potential cell attachment sites were mapped to loop I (amino acids 297 to 312) and loop II (amino acids 379-385) of the DENV-2 E using the phage-displayed truncated DENV-2 E fragments and by the analysis of the E structure. Loop II was present only in EB4 recombinant phages. There was no competition for binding to C6/36 cell proteins between EB2 and EB4 phages. Loop I and loop II are similar to the sub-complex specific and type-specific neutralizing monoclonal antibody binding sites, respectively. Hence, it is proposed that binding and entry of DENV involves the interaction of loop I to cell surface glycosaminoglycan-motif and a subsequent highly specific interaction involving loop II with other cell proteins. The phage displayed truncated DENV-2 E is a powerful and useful method for the direct determination of DENV-2 E cell binding sites.

Matched MeSH terms: Recombinant Fusion Proteins/metabolism*
Evaluation of different promoters driving the GFP reporter gene and selected target tissues for particle bombardment of Dendrobium Sonia 17

Tee CS, Marziah M, Tan CS, Abdullah MP

Plant Cell Rep, 2003 Jan;21(5):452-8.
PMID: 12789448

Three different morphological callus types, identified as type A, B and C, and tips of in vitro inflorescences were used as target tissues for genetic transformation. Five different DNA plasmids carrying a synthetic green fluorescent protein (gfp) gene driven by different promoters, CaMV 35S, HBT, and Ubi1 were tested for the genetic transformation of Dendrobium Sonia 17. 35S-sgfp-TYG-nos (p35S) with the CaMV 35S promoter showed the highest GFP transient expression rate, while the HBT and Ubi1 promoters showed a relatively lower expression rate in all of the target tissues tested. The highest number of GFP-expressing cells was observed on day 2 post-bombardment, and the number declined gradually over the course of the next 2 weeks. Type A and B callus were found to be the best potential target tissues for genetic transformation.

Matched MeSH terms: Recombinant Fusion Proteins/metabolism
Fulltext Expression of the Streptococcus pneumoniae yoeB chromosomal toxin gene causes cell death in the model plant Arabidopsis thaliana

Bakar FA, Yeo CC, Harikrishna JA

BMC Biotechnol, 2015;15:26.
PMID: 25887501 DOI: 10.1186/s12896-015-0138-8

Bacterial toxin-antitoxin systems usually comprise of a pair of genes encoding a stable toxin and its cognate labile antitoxin and are located in the chromosome or in plasmids of several bacterial species. Chromosomally-encoded toxin-antitoxin systems are involved in bacterial stress responses and activation of the toxins usually leads to cell death or dormancy. Overexpression of the chromosomally-encoded YoeB toxin from the yefM-yoeB toxin-antitoxin locus of the Gram-positive bacterium Streptococcus pneumoniae has been shown to cause cell death in S. pneumoniae as well as E. coli.

Matched MeSH terms: Recombinant Fusion Proteins/metabolism*
FISH analysis using PPAR γ-specific probes for detection of PAX8-PPAR γ translocation in follicular thyroid neoplasms

Sharifah NA, Zakaria Z, Chia WK

Methods Mol Biol, 2013;952:187-96.
PMID: 23100233 DOI: 10.1007/978-1-62703-155-4_13

Fluorescence in situ hybridization (FISH) is increasingly gaining importance in clinical diagnostics settings. Due to the ability of the technique to detect chromosomal abnormalities in samples with low cellularity or containing a mixed population of cells even at a single-cell level, it has become more popular in cancer research and diagnosis. Here, we describe the FISH technique for detection of PAX8-PPARγ translocation in follicular thyroid neoplasms, and the optimal protocol for the detection of this fusion gene using in archival formalin-fixed paraffin-embedded (FFPE) thyroid tissue sections.

Matched MeSH terms: Recombinant Fusion Proteins/metabolism
Fulltext Gene expression profiles in primary duodenal chick cells following transfection with avian influenza virus H5 DNA plasmid encapsulated in silver nanoparticles

Jazayeri SD, Ideris A, Shameli K, Moeini H, Omar AR

Int J Nanomedicine, 2013;8:781-90.
PMID: 23459681 DOI: 10.2147/IJN.S39074

In order to develop a systemically administered safe and effective nonviral gene delivery system against avian influenza virus (AIV) that induced cytokine expression, the hemagglutinin (H5) gene of AIV, A/Ck/Malaysia/5858/04 (H5N1) and green fluorescent protein were cloned into a coexpression vector pIRES (pIREGFP-H5) and formulated using green synthesis of silver nanoparticles (AgNPs) with poly(ethylene glycol) and transfected into primary duodenal cells taken from 18-day-old specific-pathogen-free chick embryos. The AgNPs were prepared using moderated temperature and characterized for particle size, surface charge, ultraviolet-visible spectra, DNA loading, and stability. AgNPs and AgNP-pIREGFP-H5 were prepared in the size range of 13.9 nm and 25 nm with a positive charge of +78 ± 0.6 mV and +40 ± 6.2 mV, respectively. AgNPs with a positive surface charge could encapsulate pIREGFP-H5 efficiently. The ultraviolet-visible spectra for AgNP-pIREGFP-H5 treated with DNase I showed that the AgNPs were able to encapsulate pIREGFP-H5 efficiently. Polymerase chain reaction showed that AgNP-pIREGFP-H5 entered into primary duodenal cells rapidly, as early as one hour after transfection. Green fluorescent protein expression was observed after 36 hours, peaked at 48 hours, and remained stable for up to 60 hours. In addition, green fluorescent protein expression generally increased with increasing DNA concentration and time. Cells were transfected using Lipocurax in vitro transfection reagent as a positive control. A multiplex quantitative mRNA gene expression assay in the transfected primary duodenal cells via the transfection reagent and AgNPs with pIREGFP-H5 revealed expression of interleukin (IL)-18, IL-15, and IL-12β.

Matched MeSH terms: Recombinant Fusion Proteins/metabolism
Glycosylation is not necessary for recognition of the fusion glycoprotein domain of the human respiratory syncytial virus by a polyclonal antibody

Lim SH, Jahanshiri F, Jalilian FA, Rahim RA, Sekawi Z, Yusoff K

Acta Virol., 2010;54(3):181-7.
PMID: 20822310

Human respiratory syncytial virus (HRSV) is a leading pathogen causing lower respiratory tract infections in infants and young children worldwide. In line with the development of an effective vaccine against HRSV, a domain of the fusion (F) glycoprotein of HRSV was produced and its immunogenicity and antigenic properties, namely the effect of deficient glycosylation was examined. A His-tagged recombinant F (rF) protein was expressed in Escherichia coli, solubilized with 8 mol/l urea, purified by the Ni-NTA affinity chromatography and used for the raising of a polyclonal antibody in rabbits. The non-glycosylated rF protein proved to be a strong immunogen that induced a polyclonal antibody that was able to recognize also the glycosylated F1 subunit of native HRSV. The other way around, a polyclonal antibody prepared against the native HRSV was able to react with the rF protein. These results indicated that glycosylation was not necessary for the F domain aa 212-574 in order to be recognized by the specific polyclonal antibody.

Matched MeSH terms: Recombinant Fusion Proteins/metabolism
Gonadotropin-inhibitory hormone promoter-driven enhanced green fluorescent protein expression decreases during aging in female rats

Soga T, Kitahashi T, Clarke IJ, Parhar IS

Endocrinology, 2014 May;155(5):1944-55.
PMID: 24605826 DOI: 10.1210/en.2013-1786

Gonadotropin-inhibitory hormone (GnIH) neurons project to GnRH neurons to negatively regulate reproductive function. To fully explore the projections of the GnIH neurons, we created transgenic rats carrying an enhanced green fluorescent protein (EGFP) tagged to the GnIH promoter. With these animals, we show that EGFP-GnIH neurons are localized mainly in the dorsomedial hypothalamic nucleus (DMN) and project to the hypothalamus, telencephalon, and diencephalic thalamus, which parallels and confirms immunocytochemical and gene expression studies. We observed an age-related reduction in c-Fos-positive GnIH cell numbers in female rats. Furthermore, GnIH fiber appositions to GnRH neurons in the preoptic area were lessened in middle-aged females (70 weeks old) compared with their younger counterparts (9-12 weeks old). The fiber density in other brain areas was also reduced in middle-aged female rats. The expression of estrogen and progesterone receptors mRNA in subsets of EGFP-GnIH neurons was shown in laser-dissected single EGFP-GnIH neurons. We then examined estradiol-17β and progesterone regulation of GnIH neurons, using c-Fos presence as a marker. Estradiol-17β treatment reduced c-Fos labeling in EGFP-GnIH neurons in the DMN of young ovariectomized adult females but had no effect in middle-aged females. Progesterone had no effect on the number of GnIH cells positive for c-Fos. We conclude that there is an age-related decline in GnIH neuron number and GnIH inputs to GnRH neurons. We also conclude that the response of GnIH neurons to estrogen diminishes with reproductive aging.

Matched MeSH terms: Recombinant Fusion Proteins/metabolism
High level expression of thermostable lipase from Geobacillus sp. strain T1

Leow TC, Rahman RN, Basri M, Salleh AB

Biosci Biotechnol Biochem, 2004 Jan;68(1):96-103.
PMID: 14745170

A thermostable extracellular lipase of Geobacillus sp. strain T1 was cloned in a prokaryotic system. Sequence analysis revealed an open reading frame of 1,251 bp in length which codes for a polypeptide of 416 amino acid residues. The polypeptide was composed of a signal peptide (28 amino acids) and a mature protein of 388 amino acids. Instead of Gly, Ala was substituted as the first residue of the conserved pentapeptide Gly-X-Ser-X-Gly. Successful gene expression was obtained with pBAD, pRSET, pET, and pGEX as under the control of araBAD, T7, T7 lac, and tac promoters, respectively. Among them, pGEX had a specific activity of 30.19 Umg(-1) which corresponds to 2927.15 Ug(-1) of wet cells after optimization. The recombinant lipase had an optimum temperature and pH of 65 degrees C and pH 9, respectively. It was stable up to 65 degrees C at pH 7 and active over a wide pH range (pH 6-11). This study presents a rapid cloning and overexpression, aimed at improving the enzyme yield for successful industrial application.

Matched MeSH terms: Recombinant Fusion Proteins/metabolism
Humanization of chimeric anti-CD20 antibody by logical and bioinformatics approach with retention of biological activity

Khoo YL, Cheah SH, Chong H

Immunotherapy, 2017 06;9(7):567-577.
PMID: 28595518 DOI: 10.2217/imt-2017-0016

AIM: To develop a fully bioactive humanized antibody from the chimeric rituximab for potential clinical applications using a relatively simpler and faster logical and bioinformatics approach.
METHODS: From bioinformatics data, mismatched mouse amino acids in variable light and heavy chain amphipathic regions were identified and substituted with those common to human antibody framework. Appropriate synthetic DNA sequences inserted into vectors were transfected into HEK293 cells to produce the humanized antibody.
RESULTS: Humanized antibodies showed specific binding to CD20 and greater cytotoxicity to cancer WIL2-NS cell proliferation than rituximab in vitro.
CONCLUSION: A humanized version of rituximab with potential to be developed into a biobetter for treatment of B-cell disorders has been successfully generated using a logical and bioinformatics approach.

Matched MeSH terms: Recombinant Fusion Proteins/metabolism
Fulltext Intracellular Delivery of Proteins via Fusion Peptides in Intact Plants

Ng KK, Motoda Y, Watanabe S, Sofiman Othman A, Kigawa T, Kodama Y, et al.

PLoS One, 2016;11(4):e0154081.
PMID: 27100681 DOI: 10.1371/journal.pone.0154081

In current plant biotechnology, the introduction of exogenous DNA encoding desired traits is the most common approach used to modify plants. However, general plant transformation methods can cause random integration of exogenous DNA into the plant genome. To avoid these events, alternative methods, such as a direct protein delivery system, are needed to modify the plant. Although there have been reports of the delivery of proteins into cultured plant cells, there are currently no methods for the direct delivery of proteins into intact plants, owing to their hierarchical structures. Here, we demonstrate the efficient fusion-peptide-based delivery of proteins into intact Arabidopsis thaliana. Bovine serum albumin (BSA, 66 kDa) was selected as a model protein to optimize conditions for delivery into the cytosol. The general applicability of our method to large protein cargo was also demonstrated by the delivery of alcohol dehydrogenase (ADH, 150 kDa) into the cytosol. The compatibility of the fusion peptide system with the delivery of proteins to specific cellular organelles was also demonstrated using the fluorescent protein Citrine (27 kDa) conjugated to either a nuclear localization signal (NLS) or a peroxisomal targeting signal (PTS). In conclusion, our designed fusion peptide system can deliver proteins with a wide range of molecular weights (27 to 150 kDa) into the cells of intact A. thaliana without interfering with the organelle-targeting peptide conjugated to the protein. We expect that this efficient protein delivery system will be a powerful tool in plant biotechnology.

Matched MeSH terms: Recombinant Fusion Proteins/metabolism*
PAK5 mediates cell: cell adhesion integrity via interaction with E-cadherin in bladder cancer cells

Ismail AF, Oskay Halacli S, Babteen N, De Piano M, Martin TA, Jiang WG, et al.

Biochem. J., 2017 Mar 24;474(8):1333-1346.
PMID: 28232500 DOI: 10.1042/BCJ20160875

Urothelial bladder cancer is a major cause of morbidity and mortality worldwide, causing an estimated 150 000 deaths per year. Whilst non-muscle-invasive bladder tumours can be effectively treated, with high survival rates, many tumours recur, and some will progress to muscle-invasive disease with a much poorer long-term prognosis. Thus, there is a pressing need to understand the molecular transitions occurring within the progression of bladder cancer to an invasive disease. Tumour invasion is often associated with a down-regulation of E-cadherin expression concomitant with a suppression of cell:cell junctions, and decreased levels of E-cadherin expression have been reported in higher grade urothelial bladder tumours. We find that expression of E-cadherin in a panel of bladder cancer cell lines correlated with the presence of cell:cell junctions and the level of PAK5 expression. Interestingly, exogenous PAK5 has recently been described to be associated with cell:cell junctions and we now find that endogenous PAK5 is localised to cell junctions and interacts with an E-cadherin complex. Moreover, depletion of PAK5 expression significantly reduced junctional integrity. These data suggest a role for PAK5 in maintaining junctional stability and we find that, in both our own patient samples and a commercially available dataset, PAK5mRNA levels are reduced in human bladder cancer compared with normal controls. Taken together, the present study proposes that PAK5 expression levels could be used as a novel prognostic marker for bladder cancer progression.

Matched MeSH terms: Recombinant Fusion Proteins/metabolism
Purification of histidine-tagged nucleocapsid protein of Nipah virus using immobilized metal affinity chromatography

Chong FC, Tan WS, Biak DR, Ling TC, Tey BT

J Chromatogr B Analyt Technol Biomed Life Sci, 2009 May 15;877(14-15):1561-7.
PMID: 19395325 DOI: 10.1016/j.jchromb.2009.03.048

Nucleocapsid (N) protein of Nipah virus (NiV) is a potential serological marker used in the diagnosis of NiV infections. In this study, a rapid and efficient purification system, HisTrap 6 Fast Flow packed bed column was applied to purify recombinant histidine-tagged N protein of NiV from clarified feedstock. The optimizations of binding and elution conditions of N protein of NiV onto and from Nickel Sepharose 6 Fast Flow were investigated. The optimal binding was achieved at pH 7.5, superficial velocity of 1.25 cm/min. The bound N protein was successfully recovered by a stepwise elution with different concentration of imidazole (50, 150, 300 and 500 mM). The N protein of NiV was captured and eluted from an inlet N protein concentration of 0.4 mg/ml in a scale-up immobilized metal affinity chromatography (IMAC) packed bed column of Nickel Sepharose 6 Fast Flow with the optimized condition obtained from the method scouting. The purification of histidine-tagged N protein using IMAC packed bed column has resulted a 68.3% yield and a purification factor of 7.94.

Matched MeSH terms: Recombinant Fusion Proteins/metabolism

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