Stable Cell Line Development Service – Constitutive Expression

Our proprietary ExoIN technology is a powerful and reliable platform for the development of customized assay cell lines with stable and homogeneous target expression. Using this technology, we are able to generate your desired mammalian cell line to support your specific project research requirements within weeks instead of months. All we need is your target gene 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 selection marker. This means that once selected, the stable cell pool transcribes the target protein almost homogeneously (e.g. reference protein expression GFP > 90%).

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.

graphic of trenzyme's ExoIN technology - used in the cell line development

By loading the video, you agree to YouTube's privacy policy.
Learn more

Load video

Main Advantages of trenzyme’s ExoIN Technology

  • Generation of ready-to-use stable assay cell lines within weeks instead of months –  depending on target and parental cell line no single cell cloning is needed.
  • Fast feasibility answer since transient test is predictive for stable cell line.
  • The appearance of false-positive cells (resistant to selection marker but without target expression) can be minimized by our ExoIN technology.
  • ExoIN technology is applicable to any cell line and all target classes.
  • Target remains unmodified and functional.
  • Continuous selection of target expression on protein level (no silencing / no stability issues).
  • Easy co-expression of different targets (three or even more).
  • Homogenous recombinant expression within cell pool.
  • Reliable and powerful platform – more than 1,000 generated cell lines for international clients.
timeline for comparison of conventional and ExoIN technologies used for the stable cell line development service

“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

diagram of the process of stable cell line development - constitutive expression

Broad experience with cell lines and target classes

Overview of the many different cell lines and target classes our scientific experts have already worked with. More cell lines and target classes available on request.

Cell Lines

Human Cell Lines
  • HEK293
  • HT1080
  • Jurkat
  • NK92
  • MCF-7
  • RPE-1
  • Raji
  • MDAH-041
  • K562
Murine Cell Lines
  • A20
  • NIH3T3
  • NSC-34
  • NSO
Rat Cell Lines
  • PC12
  • Rat2
  • MRMT-1
Hamster Cell Lines
  • CHO-K1
  • CHO-S
  • CHO-G alpha 16

Target Classes

Transmembrane Receptors
  • Thyrosine kinase receptor
  • Thyrosine phosphate receptor
  • G protein coupled receptor
  • Integrin receptors
Cell Surface Proteins
  • Cell surface receptors
Channel & Transporter Proteins
  • Potassium channel
  • Sodium-dependent dopamine transporter
  • Glucose transporter
  • Glutamate/aspartate transporter
Intracellular Proteins
  • Protein kinase inhibitor
Secreted Proteins
  • Antibodies
  • Extracellular matrix proteins
Other Targets
  • Gqi5
  • Tet repressor
  • Various reporter proteins

Stable Cell Line Development Service - Overview

Quality Control Assays

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

Included Analysis:

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

Optional Analysis:

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


Further Options for Cell Line Development


Constitutive Expression FAQs
How many vials and how many cells per vial are delivered?
Our standard delivery comprises 3 cryovials per stable pool and 3 cryovials per each of the 3 best clones with 1e6 cells per vial for adherent cells or up to 1e7 cells for suspensions cells. Additional vials are possible on request.
Do royalties have to be paid?
The ExoIN cell lines are royalty free.
How many clones do you generate?
Our standard is to expand 30 and test up to 24 clones by the agreed method and deliver the best three clones according the analyses. If you have other requirements, we will discuss your needs and can adapt our standard service to a certain extent.
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 about our cell line services and/or processes – our scientific experts will reply shortly.
Get In Contact With Our Scientific Experts

    By submitting this form, I consent to trenzyme GmbH receiving and processing my data in order to process my inquiry. My consent is voluntary and I may revoke this consent at any time without providing any reasons, e.g. by sending an email to privacy(at) with effect for the future. Further notices on data processing can be found in our privacy policy.