Protein Expression Eukaryotic cells - P. pastoris GFP

Protein expression refers to the techniques in which a protein of interest is synthesized, modified or regulated in cells. The blueprints for proteins are stored in DNA which is then transcribed to produce messenger RNA (mRNA). mRNA is then translated into protein. In prokaryotes, this process of mRNA translation occurs simultaneously with mRNA transcription. In eukaryotes, these two processes occur at separate times and in separate cellular regions (transcription in nucleus and translation in the cytoplasm). Recombinant protein expression utilizes cellular machinery to generate proteins, instead of chemical synthesis of proteins as it is very complex. Proteins produced from such DNA templates are called recombinant proteins and DNA templates are simple to construct. Recombinant protein expression involves transfecting cells with a DNA vector that contains the template. The cultured cells can then transcribe and translate the desired protein. The cells can be lysed to extract the expressed protein for subsequent purification. Both prokaryotic and eukaryotic protein expression systems are widely used. The selection of the system depends on the type of protein, the requirements for functional activity and the desired yield. These expression systems include mammalian, insect, yeast, bacterial, algal and cell-free. Each of these has pros and cons. Mammalian expression systems can be used for transient or stable expression, with ultra high-yield protein expression. However, high yields are only possible in suspension cultures and more demanding culture conditions. Insect cultures are the same as mammalian, except that they can be used as both static and suspension cultures. These cultures also have demanding culture conditions and may also be time-consuming. Yeast cultures can produce eukaryotic proteins and are scalable, with minimum culture requirements. Yeast cultures may require growth culture optimization. Bacterial cultures are simple, scalable and low cost, but these may require protein-specific optimization and are not suitable for all mammalian proteins. Algal cultures are optimized for robust selection and expression, but these are less developed than other host platforms. Cell-free systems are open, free of any unnatural compounds, fast and simple. This system is, however, not optimal for scaling up.

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Found 5 matching solutions for this experiment

pD912

Robert Speight, Queensland University of Technology, Brisbane, Q

Protocol tips
P. pastoris cells were transformed following a condensed standard protocol (58). The amounts of DNA used were adjusted depending on the vector size (see Results). After the transformation, screenings and rescreenings of the indicated numbers of transformants (Fig. 2 and ​and3)3) were performed as outlined previously (13, 28, 30).
P_AOX1Syn

"Anton Glieder, Institute of Molecular Biotechnology, Graz Unive

Protocol tips
Each plasmid was amplified in E. coli, linearized with BglII or SmiI (Fermentas) and transformed into the corresponding P. pastoris strains. Single colonies were transferred to 96-well deep-well plates for standard cultivation as described previously [42]. To compare the expression levels, GFP fluorescence was measured as described by [47].
P_GAP

"Anton Glieder, Institute of Molecular Biotechnology, Graz Unive

Protocol tips
Each plasmid was amplified in E. coli, linearized with BglII or SmiI (Fermentas) and transformed into the corresponding P. pastoris strains. Single colonies were transferred to 96-well deep-well plates for standard cultivation as described previously [42]. To compare the expression levels, GFP fluorescence was measured as described by [47].
pPuzzle-eGFP

Diethard Mattanovich, Austrian Centre of Industrial Biotechnolog

Protocol tips
Plasmids were linearized within the genome integration region prior to electroporation (2 kV, 4 ms, GenePulser, BioRad) into electrocompetent P. pastoris. Multicopy integration of HSA expressing clones was done as described by Marx et al. [19] and selected at higher Zeocin concentrations (up to 1000 μg mL-1).
pPuzzle

Brigitte Gasser, Department of Biotechnology, BOKU, University o

Protocol tips
After digestion with AscI and BspHI the transformation of the P. pastoris wild type strain X-33 was performed by electroporation. The repressible promoter cassette should interact with the genomic DNA in the cell and replace the respective promoter of the gene of interest (Figure 4B) [15].
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