Combination of FACS and homologous recombination for the generation of stable and high-expression engineered cell lines

PLoS One. 2014 Mar 19;9(3):e91712. doi: 10.1371/journal.pone.0091712. eCollection 2014.

Abstract

Traditionally, cell line generation requires several months and involves screening of over several hundred cell clones for high productivity before dozens are selected as candidate cell lines. Here, we have designed a new strategy for the generation of stable and high-expression cell lines by combining homologous recombination (HR) and fluorescence-activated cell sorting (FACS). High expression was indicated by the expression of secreted green fluorescent protein (SEGFP). Parental cell lines with the highest expression of SEGFP were then selected by FACS and identified by stability analysis. Consequently, HR vectors were constructed using the cassette for SEGFP as the HR region. After transfecting the HR vector, the cells with negative SEGFP expression were enriched by FACS. The complete exchange between SEGFP and target gene (TNFR-Fc) cassettes was demonstrated by DNA analysis. Compared with the traditional method, by integrating the cassette containing the gene of interest into the pre-selected site, the highest producing cells secreted a more than 8-fold higher titer of target protein. Hence, this new strategy can be applied to isolated stable cell lines with desirable expression of any gene of interest. The stable cell lines can rapidly produce proteins for researching protein structure and function and are even applicable in drug discovery.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CHO Cells
  • Cell Engineering / methods*
  • Clone Cells
  • Cricetulus
  • Electroporation
  • Etanercept
  • Flow Cytometry*
  • Founder Effect
  • Gene Expression*
  • Genetic Vectors
  • Green Fluorescent Proteins / genetics*
  • Green Fluorescent Proteins / metabolism
  • Homologous Recombination*
  • Immunoglobulin G / biosynthesis
  • Immunoglobulin G / genetics*
  • Receptors, Tumor Necrosis Factor / biosynthesis
  • Receptors, Tumor Necrosis Factor / genetics*
  • Selection, Genetic
  • Transfection
  • Transgenes

Substances

  • Immunoglobulin G
  • Receptors, Tumor Necrosis Factor
  • Green Fluorescent Proteins
  • Etanercept

Grants and funding

This work was supported by The National “Twelfth Five-Year Plan” from the Ministry of Health (2011ZX09506-007). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.