Stable Cell Line Development Service – Constitutive Expression

Our proprietary ExoIN technology is a powerful and reliable platform for generating customized assay cell lines with stable and homogeneous target expression. Using this technology, we are able to generate your desired mammalian cell line according to your specific project requirements within weeks instead of months. All we need is your target sequence to start your project.


trenzyme’s ExoIN Technology – Modules & Explanation

The ExoIN technology links target protein expression to the expression of a resistance marker. The target, the selection marker and the ExoIN module are transcribed together as a single mRNA transcript. Subsequent efficient cotranslational cleavage at the ribosome yields the desired target protein unmodified and functional in a 1-to-1 stoichiometry with the marker. This means that once selected, the stable cell pool transcribes the target protein almost homogeneously (e.g. reference protein expression GFP > 80%).

This unique technology allows an easy and highly efficient selection of homogeneous cell populations – in consequence, time consuming and expensive single cell cloning is no longer necessary for many applications.


Main Advantages of trenzyme’s ExoIN Technology

  • Generation of ready-to-use stable assay cell lines within weeks instead of months – no time-consuming single cell cloning needed for many applications.
  • Fast feasibility answer – cell growth under selection conditions correlates with target expression.
  • The appearance of false-positive cells (resistant to selection marker but without target expression) can be minimized by the fusion protein approach of our ExoIN technology.
  • ExoIN technology is applicable to any cell line and all classes of target proteins.
  • Due to perfect cotranslational cleavage the target remains unmodified and functional. No uncut fusion proteins detectable.
  • Tunable target expression by simply modifying the selection pressure. The expression level remains stable as long as the selection pressure is constant.
  • Three different selection markers (puromycin, hygromycin and zeocin) allowing simultaneous selection up to three targets.

„We were astonished by trenzyme’s recently delivered custom ExoIN cell lines. Even „difficult-to-express“ constructs show stable and robust expression. I highly recommend trenzyme’s cell line development service.“

PD Dr. Dieter Wicher

Max Planck Institute for Chemical Ecology, Jena, Germany


Process of Stable Cell Line Development


Stable Cell Line Development Service - Overview

Quality Control Assays

To ensure highest quality and validity we offer a broad range of quality control assays for our cell line development services.


  • Mycoplasma check provided by our partner Eurofins Genomics
  • Viability assay
  • Sterility assay
  • Assessment of target expression: mRNA (via qPCR) or protein (via FACS or Western Blot)


  • Cell based assay for validation: e.g. Calcium flux assay, apoptosis assay, reporter assays or phosphorylation assessment
  • Microscopic analysis
  • Cell line authentication by STR profiling
  • Copy number determination


Further Options for Cell Line Development

  • Provide your preferred parental cell line and/or your expression system of choice and we will generate the recombinant cell line according to your needs.
  • Inducible target expression


Dr. Antje Fuhrmann, PhD

Dr. Antje Fuhrmann, PhD

Application & Sales Manager

We would be happy to provide you with support on your cell line research project. Let us know your questions and requests, our scientific experts will reply shortly.

Get In Contact With Our Scientific Experts

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