title: Identification of anti-repressor elements that confer high and stable protein production in mammalian cells.
abstract: The expression of transgenic proteins is often low and unstable over time, a problem that may be due to integration of the transgene in repressed chromatin. We developed a screening technology to identify genetic elements that efficiently counteract chromatin-associated repression. When these elements were used to flank a transgene, we observed a substantial increase in the number of mammalian cell colonies that expressed the transgenic protein. Expression of the shielded transgene was, in a copy number-dependent fashion, substantially higher than the expression of unprotected transgenes. Also, protein production remained stable over an extended time period. The DNA elements are small, not exceeding 2,100 base pairs (bp), and they are highly conserved between human and mouse, at both the functional and sequence levels. Our results demonstrate the existence of a class of genetic elements that can readily be applied to more efficient transgenic protein production in mammalian cells.
authors.affiliation: Swammerdam Institute for Life Sciences, BioCentrum Amsterdam, University of Amsterdam, Plantage Muidergracht 12, 1018 TV Amsterdam, The Netherlands.
authors.forename: Ted H J
authors.initials: TH
authors.lastname: Kwaks
authors.forename: Phil
authors.initials: P
authors.lastname: Barnett
authors.forename: Wieger
authors.initials: W
authors.lastname: Hemrika
authors.forename: Tjalling
authors.initials: T
authors.lastname: Siersma
authors.forename: Richard G A B
authors.initials: RG
authors.lastname: Sewalt
authors.forename: David P E
authors.initials: DP
authors.lastname: Satijn
authors.forename: Janynke F
authors.initials: JF
authors.lastname: Brons
authors.forename: Rik
authors.initials: R
authors.lastname: van Blokland
authors.forename: Paul
authors.initials: P
authors.lastname: Kwakman
authors.forename: Arle L
authors.initials: AL
authors.lastname: Kruckeberg
authors.forename: Angèle
authors.initials: A
authors.lastname: Kelder
authors.forename: Arie P
authors.initials: AP
authors.lastname: Otte
mesh_terms: D000818:Animals; D016466:CHO Cells; D002843:Chromatin / Q000235:genetics* / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D020869:Gene Expression Profiling / Q000379:methods*; D005786:Gene Expression Regulation / Q000235:genetics*; D006801:Humans; D008322:Mammals; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis; D015202:Protein Engineering / Q000379:methods; D011506:Proteins / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis* / Q000235:genetics*; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D019076:Transgenes / Q000235:genetics*
chemical_list: D002843:Chromatin; D011506:Proteins; D011994:Recombinant Proteins; D012097:Repressor Proteins