Inducible Protein Production in 293 Cells Using the piggyBac Transposon System

A Versatile Method for Inducible Protein Production in 293 Cells Using the PiggyBac Transposon System

The production of recombinant proteins has helped in understanding of their function and developing new therapies. However, one of the major bottlenecks for protein production is the establishment of reliable mammalian cell lines with high expression levels. In this chapter, we describe a simple and robust system that allows for the quick establishment of stable transgenic 293 cell lines with reproducible and high protein expression levels. This methodology is based on the piggyBac transposon system and enables the inducible production of the protein of interest. Finally, this methodology can easily be used in conventional laboratory cell culture settings without requiring specialized devices.

Transgene Expression and Transposition Efficiency of Two-Component Sleeping Beauty Transposon Vector Systems Utilizing Plasmid or mRNA Encoding the Transposase

The use of two-component transposon plasmid vector systems, namely, a transposase construct and a donor vector carrying the gene of interest (GOI) can accelerate the development of recombinant cell lines. However, the undesired stable transfection of the transposase construct and the sustained expression of the enzyme can cause genetic instability due to the re-mobilization of the previously transposed donor vectors. Using a Sleeping Beauty-derived vector system, we established three recombinant cell pools and demonstrate stable integration of the transposase construct and sustained expression of the transposase over a period of 48 days. To provide an alternative approach, transcripts of the transposase gene were generated in vitro and co-transfected with donor vector plasmid at different ratios and mediating high GOI copy number integrations and expression levels. We anticipate that the use of transposase mRNA will foster further improvements in future cell line development processes.

Transposon vector-mediated stable gene transfer for the accelerated establishment of recombinant mammalian cell pools allowing for high-yield production of biologics

Stable recombinant mammalian cells are of growing importance in pharmaceutical biotechnology production scenarios for biologics such as monoclonal antibodies, growth and blood factors, cytokines and subunit vaccines. However, the establishment of recombinant producer cells using classical stable transfection of plasmid DNA is hampered by low stable gene transfer efficiencies. Consequently, subsequent selection of transgenic cells and the screening of clonal cell populations are time- and thus cost-intensive. To overcome these limitations, expression cassettes were embedded into transposon-derived donor vectors. Upon the co-transfection with transposase-encoding constructs, elevated vector copy numbers stably integrated into the genomes of the host cells are readily achieved facilitating under stringent selection pressure the establishment of cell pools characterized by sustained and high-yield recombinant protein production. Here, we discuss some aspects of transposon vector technologies, which render these vectors promising candidates for their further utilization in the production of biologics.

What Happened to the Participants of the Math Olympiad 1971? A Multiple-Case Study Concerning the Occupational Success of the Winning Team from Hungary, Math Olympiad–Occupational Success

The aim of this multiple-case study was to find out how the most successful team of the 1971 Mathematical Olympiad in Hungary developed professionally. It is impressive that in 1971, no fewer than four participants on the Hungarian team received gold medals and four participants received silver medals. Seven of the eight analyzed participants on the team came from a grammar school in Budapest. Three of the four gold medal winners achieved remarkable academic positions. On average, professional positions were achieved (as scored by the magnitude prestige scale) well above the average for a normal grammar school sample. Interestingly, the calculated average of the Hungarian team (156.5 ± 15.5) was slightly higher than that of the comparison team from Sweden (142.8 ± 30.5), but this difference was not significant (p = 0.351). In principle, excellence seems to result in excellence. For several former participants on the Hungarian team, it was shown that they continued to be extremely successful in the field of mathematics, with a thematic focus in the field of statistics and probability calculations.