Send to:

Choose Destination
See comment in PubMed Commons below
Nucleic Acids Res. 2013 Jan 7;41(1):e29. doi: 10.1093/nar/gks940. Epub 2012 Oct 15.

Selection of a T7 promoter mutant with enhanced in vitro activity by a novel multi-copy bead display approach for in vitro evolution.

Author information

  • 1Department of Molecular and Medical Virology, Ruhr-University Bochum, D-44780 Bochum, Germany.


In vitro evolution of nucleic acids and proteins is a powerful strategy to optimize their biological and physical properties. To select proteins with the desired phenotype from large gene libraries, the proteins need to be linked to the gene they are encoded by. To facilitate selection of the desired phenotype and isolation of the encoding DNA, a novel bead display approach was developed, in which each member of a library of beads is first linked to multiple copies of a clonal gene variant by emulsion polymerase chain reaction. Beads are transferred to a second emulsion for an in vitro transcription-translation reaction, in which the protein encoded by each bead's amplicon covalently binds to the bead present in the same picoliter reactor. The beads then contain multiple copies of a clonal gene variant and multiple molecules of the protein encoded by the bead's gene variant and serve as the unit of selection. As a proof of concept, we screened a randomized library of the T7 promoter for high expression levels by flow cytometry and identified a T7 promoter variant with an ~10-fold higher in vitro transcriptional activity, confirming that the multi-copy bead display approach can be efficiently applied to in vitro evolution.

[PubMed - indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk