scholarly journals Functional expression of TrpC1: a human homologue of the Drosophila Trp channel

1998 ◽  
Vol 331 (1) ◽  
pp. 331-339 ◽  
Author(s):  
William G. SINKINS ◽  
Mark ESTACION ◽  
William P. SCHILLING
Keyword(s):  
Post Infection ◽  
Mammalian Cells ◽  
Expression System ◽  
Baculovirus Expression System ◽  
Functional Expression ◽  
Sf9 Cells ◽  
Infection Time ◽  
A Subunit ◽  
High Concentrations ◽  
Inwardly Rectifying

TrpC1 appears to be a store-operated channel (SOC) when expressed in mammalian cells. In the present study, TrpC1 was expressed in Sf9 insect cells using the baculovirus expression system. Expression of TrpC1 caused an increase in basal cytosolic free Ca2+ concentration ([Ca2+]i) as a function of post-infection time. Basal Ba2+ influx, an index of plasmalemmal Ca2+ permeability, was also increased and was blocked by La3+. Although the thapsigargin-induced change in [Ca2+]i was greater in TrpC1-expressing cells than controls, Ba2+ influx was unaffected by thapsigargin. Whole-cell membrane currents recorded in TrpC1-expressing cells increased as a function of post-infection time and were (1) inwardly rectifying in symmetrical sodium gluconate solutions, (2) non-selective with respect to Na+, Ca2+ and Ba2+, and (3) blocked by La3+. Furthermore TrpC1 currents were unaffected by (1) thapsigargin, (2) dialysis of the cell with Ins(1,4,5)P3 or (3) dialysis of the cell with solutions containing high concentrations of the Ca2+ chelator, EGTA. These results suggest that TrpC1 forms non-selective cation channels that are constitutively active when expressed in Sf9 cells, but insensitive to depletion of the internal Ca2+ stores. Thus TrpC1 may be a subunit of a SOC which alone can form functional channels in Sf9 cells, but which requires additional subunits or cytoplasmic factors present in mammalian cells for expression of SOC activity.

Functional Expression of Gastric H,K-ATPase in Sf9 Cells using the Baculovirus Expression System

1994 ◽  
pp. 19-26
Author(s):  
Corné H. W. Klaassen ◽  
Tom J. F. Van Uem ◽  
Mariëlle P. De Moel ◽  
Godelieve L. J. De Caluwé ◽  
Herman G. P. Swarts ◽  
...  
Keyword(s):  
Expression System ◽  
Baculovirus Expression System ◽  
Functional Expression ◽  
Sf9 Cells ◽  
Baculovirus Expression

scholarly journals Characterization and purification of human retinoic acid receptor-γ 1 overexpressed in the baculovirus-insect cell system

1992 ◽  
Vol 287 (3) ◽  
pp. 833-840 ◽  
Author(s):  
A P Reddy ◽  
J Y Chen ◽  
T Zacharewski ◽  
H Gronemeyer ◽  
J J Voorhees ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Dna Binding ◽  
Mammalian Cells ◽  
Retinoic Acid Receptor ◽  
Expression System ◽  
Gel Filtration ◽  
Recombinant Baculovirus ◽  
Sf9 Cells ◽  
Acid Receptor ◽  
Gel Retardation

The full-length cDNA for the human retinoic acid receptor-gamma 1 (RAR-gamma 1) has been expressed to high levels in Spodoptera frugiferda (Sf9) cells using the baculovirus expression system. Western blot analysis revealed that RAR-gamma 1 expression increased between 32 and 60 h post-infection. The recombinant receptor was expressed primarily as a nuclear protein and displayed a molecular mass of 50 kDa as determined by SDS/PAGE and gel-filtration chromatography, consistent with its cDNA-deduced size. Based on ligand binding, 2 x 10(6) RAR-gamma 1 molecules were expressed per Sf9 cell, a level approx. 2000 times greater than in mammalian cells. The receptor was partially purified 300-fold by sequential anion-exchange, gel-filtration and DNA affinity chromatographies. The overexpressed receptor specifically bound all-trans-retinoic acid (RA) and the synthetic retinoid CD367 with high affinity (Kd 0.15 nM and 0.23 nM respectively). The RA metabolites 4-hydroxy-RA and 4-oxo-RA were poor competitors for [3H]CD367 binding to recombinant RAR-gamma 1 (K(i) > 1 microM), indicating that 4-oxidation of RA greatly reduces its affinity for RAR-gamma 1. Gel-retardation analysis demonstrated that RAR-gamma 1 specifically bound the RA response element of the mouse RAR-beta gene. RAR-gamma 1 species expressed from recombinant baculovirus (in Sf9 cells) and vaccinia virus (in HeLa cells) exhibited similar affinities for RA and CD367 and had comparable DNA-binding properties in gel-retardation experiments. Moreover, a similar requirement for additional DNA-binding stimulatory factor(s) was observed in both cases. These results provide a basis for the use of baculovirus-expressed RAR-gamma 1 in further functional and structural studies.

scholarly journals Cloning and expression of a chick liver glutathione S-transferase CL 3 subunit with the use of a baculovirus expression system

1992 ◽  
Vol 281 (2) ◽  
pp. 545-551 ◽  
Author(s):  
L H Chang ◽  
J Y Fan ◽  
L F Liu ◽  
S P Tsai ◽  
M F Tam
Keyword(s):  
Specific Activity ◽  
Sequence Similarity ◽  
Expression System ◽  
Baculovirus Expression System ◽  
Relative Activity ◽  
Cloning And Expression ◽  
Glutathione S Transferase ◽  
Sds Page ◽  
Glutathione S Transferases ◽  
A Subunit

Glutathione S-transferase CL 3 subunits purified from 1-day-old-chick livers were digested with Achromobacter proteinase I and the resulting fragments were isolated for amino acid sequence analysis. An oligonucleotide probe was constructed accordingly for cDNA library screening. A cDNA clone of 1342 bases, pGCL301, encoding a protein of 26209 Da was isolated and sequenced. Including conservative substitutions, this protein has 75-79% sequence similarity to other Alpha family glutathione S-transferases. The coding sequence of pGCL301 was inserted into a baculovirus vector for infection of Spodoptera frugiperda (SF9) cells. The expressed protein has a high relative activity with ethacrynic acid (47% of the specific activity with 1-chloro-2,4-dinitrobenzene). The enzyme has a subunit molecular mass of 25.2 +/- 1.2 kDa (by SDS/PAGE), a pI of 9.45 and an absorption coefficient A1%1cm of 13.0 +/- 0.5 at 280 nm.

scholarly journals The Xenopus tropicalis orthologue of TRPV3 is heat sensitive

2015 ◽  
Vol 146 (5) ◽  
pp. 411-421 ◽  
Author(s):  
Beiying Liu ◽  
Feng Qin
Keyword(s):  
Mammalian Cells ◽  
Xenopus Oocytes ◽  
Transient Receptor Potential ◽  
Trp Channels ◽  
Expression System ◽  
Receptor Potential ◽  
Functional Expression ◽  
Cold Sensitivity ◽  
Mammalian Cell Lines ◽  
Transient Receptor

Thermosensitive members of the transient receptor potential (TRP) family of ion channels (thermal TRP channels) play a crucial role in mammalian temperature sensing. Orthologues of these channels are present in lower vertebrates and, remarkably, some thermal TRP orthologues from different species appear to mediate opposing responses to temperature. For example, whereas the mammalian TRPV3 channel is activated by heat, frog TRPV3 is reportedly activated by cold. Intrigued by the potential implications of these opposing responses to temperature for the mechanism of temperature-dependent gating, we cloned Xenopus laevis TRPV3 and functionally expressed it in both mammalian cell lines and Xenopus oocytes. We found that, when expressed in mammalian cells, the recombinant channel lacks the reported cold sensitivity; rather, it is activated by temperatures >50°C. Furthermore, when expressed in mammalian cells, the frog orthologue shows other features characteristic of mammalian TRPV3, including activation by the agonist 2-aminoethoxydiphenyl borate and an increased response with repeated stimulation. We detected both heat- and cold-activated currents in Xenopus oocytes expressing the recombinant frog TRPV3 channel. However, cold-activated currents were also apparent in control oocytes lacking recombinant TRPV3. Our data indicate that frog TRPV3 resembles its mammalian orthologues in terms of its thermosensitivity and is intrinsically activated by heat. Thus, all known vanilloid receptors are activated by heat. Our data also show that Xenopus oocytes contain endogenous receptors that are activated by cold, and suggest that cold sensitivity of TRP channels established using Xenopus oocytes as a functional expression system may need to be revisited.

Molecular structure and function of CD4 on murine egg plasma membrane

Zygote ◽  
1995 ◽  
Vol 3 (1) ◽  
pp. 65-73 ◽  
Author(s):  
Mao Wu Guo ◽  
Toshiki Watanabe ◽  
Etsuko Mori ◽  
Tsuneatsu Mori
Keyword(s):  
Plasma Membrane ◽  
Mhc Class Ii ◽  
Expression System ◽  
Direct Interaction ◽  
Baculovirus Expression System ◽  
Class Ii ◽  
Sf9 Cells ◽  
Sperm Cells ◽  
Nuclear Polyhedrosis ◽  
And Function

SummaryIn the present study, the expression of the CD4 molecule on murine egg plasma membrane was confirmed by the indirect immunofluorescence (IIF) method. The full-length CD4 cDNA from murine eggs was synthesised by the reverse transcriptase-polymerase chain reaction (RT-PCR) method and its authenticity verified by Southern blot hybridisation using an end-labelled internal oligonucleotide. The results of DNA sequencing showed that the nucleotide sequence of the cDNA of CD4 from murine egg mRNA was identical to that of immune T cells. To demonstrate the direct interaction of CD4 from murine egg with murine sperm cells bearing MHC (major histocompatibility complex) class II molecule, we employed a baculovirus expression system to generate CD4 on the surface of Spodoptera frugiperda (Sf9) cells. Expression of CD4 on Sf9 cells infected with autographa californica nuclear polyhedrosis virus (AcNPV)-CD4 was demonstrated by IIF and immunoblotting. The CD4-expressing Sf9 cells adhered to MHC class II-bearing sperm cells since the adhension was specifically blocked by anti-CD4 monoclonal antibody (mAb) or anti-monomorphic region of MHC class II mAb. Taking our previous and present experimental results together, they strongly suggest that intercellular membrane adhesion between two gametes at the fusion step in fertilisation is mediated by the MHC class II molecule located on the posterior region of the sperm head and the CD4 molecule on egg plasma membrane.

scholarly journals Functional expression of P-glycoprotein in Saccharomyces cerevisiae confers cellular resistance to the immunosuppressive and antifungal agent FK520

1994 ◽  
Vol 14 (1) ◽  
pp. 277-286
Author(s):  
M Raymond ◽  
S Ruetz ◽  
D Y Thomas ◽  
P Gros
Keyword(s):  
Multidrug Resistance ◽  
Mammalian Cells ◽  
Drug Transport ◽  
Function Analysis ◽  
Expression System ◽  
Functional Expression ◽  
Yeast Cells ◽  
Mutant Form ◽  
Cellular Resistance ◽  
P Glycoprotein

We have recently reported that expression in yeast cells of P-glycoprotein (P-gp) encoded by the mouse multidrug resistance mdr3 gene (Mdr3) can complement a null ste6 mutation (M. Raymond, P. Gros, M. Whiteway, and D. Y. Thomas, Science 256:232-234, 1992). Here we show that Mdr3 behaves as a fully functional drug transporter in this heterologous expression system. Photolabelling experiments indicate that Mdr3 synthesized in yeast cells binds the drug analog [125I]iodoaryl azidoprazosin, this binding being competed for by vinblastine and tetraphenylphosphonium bromide, two known multidrug resistance drugs. Spheroplasts expressing wild-type Mdr3 (Ser-939) exhibit an ATP-dependent and verapamil-sensitive decreased accumulation of [3H]vinblastine as compared with spheroplasts expressing a mutant form of Mdr3 with impaired transport activity (Phe-939). Expression of Mdr3 in yeast cells can confer resistance to growth inhibition by the antifungal and immunosuppressive agent FK520, suggesting that this compound is a substrate for P-gp in yeast cells. Replacement of Ser-939 in Mdr3 by a series of amino acid substitutions is shown to modulate both the level of cellular resistance to FK520 and the mating efficiency of yeast mdr3 transformants. The effects of these mutations on the function of Mdr3 in yeast cells are similar to those observed in mammalian cells with respect to drug resistance and transport, indicating that transport of a-factor and FK520 in yeast cells is mechanistically similar to drug transport in mammalian cells. The ability of P-gp to confer cellular resistance to FK520 in yeast cells establishes a dominant phenotype that can be assayed for the positive selection of intragenic revertants of P-gp inactive mutants, an important tool for the structure-function analysis of mammalian P-gp in yeast cells.

Production of recombinant new canine parvovirus 2a viral protein 2 in SF9 cells using a baculovirus expression system

2020 ◽  
Vol 44 (3) ◽  
pp. 142-145
Author(s):  
Hyeonhae Choi ◽  
Seyeon Park ◽  
Yoon-Hee Lee ◽  
Ju-Yeon Lee ◽  
Jae Young Song ◽  
...  
Keyword(s):  
Viral Protein ◽  
Expression System ◽  
Baculovirus Expression System ◽  
Canine Parvovirus ◽  
Sf9 Cells ◽  
Baculovirus Expression

Expression and characterization of recombinant human α-3/4-fucosyltransferase III from Spodoptera frugiperda (Sf9) and Trichoplusia ni (Tn) cells using the baculovirus expression system

2001 ◽  
Vol 353 (3) ◽  
pp. 719-725 ◽  
Author(s):  
Vanessa A. MORAIS ◽  
Jacinta SERPA ◽  
Angelina S. PALMA ◽  
Teresa COSTA ◽  
Luís MARANGA ◽  
...  
Keyword(s):  
Cell Lines ◽  
Trichoplusia Ni ◽  
Secretory Pathway ◽  
Expression System ◽  
Baculovirus Expression System ◽  
Exchange Chromatography ◽  
Sf9 Cells ◽  
Type I ◽  
Baculovirus Expression ◽  
Insect Cell Lines

The human α-3/4-fucosyltransferase III (Fuc-TIII) participates in the synthesis of Lewis determinants. The enzyme from human sources is scarce and heterogeneous. In this paper we describe the expression of a secreted form of Fuc-TIII (SFT3) in two insect cell lines, Spodopterafrugiperda (Sf9) and Trichoplusiani (Tn), using the baculovirus expression system. The Sf9 cells secreted approx. 0.4unit/l (1mg/l) of the enzyme. The Tn cells secreted approx. 3-fold this amount. A large proportion of active protein was accumulated in the two cell lines (50 and 75% respectively for Sf9 and Tn cells, on the fourth day after infection) indicating a possible limitation not only of the folding machinery, but also a saturation of the secretory pathway. SFT3 was purified by cation-exchange chromatography followed by affinity chromatography. The enzyme from the Tn cell line had a lower global charge, possibly due to post-translational modifications, such as phosphorylation or sulphation. The two glycosylation sites from SFT3 were occupied. SFT3 secreted by Sf9 cells was completely deglycosylated by peptide-N-glycanase F, whereas 50% of SFT3 secreted by Tn cells was resistant to deglycosylation by this enzyme. The apparent kinetic parameters determined with the type I acceptor were kcat = 0.4s-1 and Km = 0.87mM for the SFT3 secreted by Tn cells, and kcat = 0.09s-1 and Km = 0.76mM for the SFT3 secreted by Sf9 cells, indicating that the enzymes had substrate affinities within the same order of magnitude as their mammalian counterpart. Furthermore, SFT3 secreted by either cell type showed a clear preference for type 1 carbohydrate acceptors, similarly to human Fuc-TIII.

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