title: Identification of transgene integration loci of different highly expressing recombinant CHO cell lines by FISH.
abstract: Recombinant CHO cell lines have integrated the expression vectors in various parts of the genome leading to different levels of gene amplification, productivity and stability of protein expression. Identification of insertion sites where gene amplification is possible and the transcription rate is high may lead to systems of site-directed integration and will significantly reduce the process for the generation of stably and highly expressing recombinant cell lines. We have investigated a broad range of recombinant cell lines by FISH analysis and Giemsa-Trypsin banding and analysed their integration loci with regard to the extent of methotrexate pressure, transfection methods, promoters and protein productivities. To summarise, we found that the majority of our high producing recombinant CHO cell lines had integrated the expression construct on a larger chromosome of the genome. Furthermore, except from two cell lines, the exogene was integrated at a single site. The dhfr selection marker was co-localised to the target gene.
authors.affiliation: Austrian Center of Biopharmaceutical Technology, Muthgasse 18, 1190, Vienna, Austria, christine.lattenmayer@malteser.at.
authors.forename: Christine
authors.initials: C
authors.lastname: Lattenmayer
authors.forename: Martina
authors.initials: M
authors.lastname: Loeschel
authors.forename: Willibald
authors.initials: W
authors.lastname: Steinfellner
authors.forename: Evelyn
authors.initials: E
authors.lastname: Trummer
authors.forename: Dethardt
authors.initials: D
authors.lastname: Mueller
authors.forename: Kornelia
authors.initials: K
authors.lastname: Schriebl
authors.forename: Karola
authors.initials: K
authors.lastname: Vorauer-Uhl
authors.forename: Hermann
authors.initials: H
authors.lastname: Katinger
authors.forename: Renate
authors.initials: R
authors.lastname: Kunert