Technical Service

Mammalian Cell Expression System


1.Vector Construction

(1) cDNA can be cloned into the expression vector of mammalian cells provided by customers or AtaGenix.

(2) Secretion signal peptides and purification tags can be added to the expression vector to promote protein secretion expression and meet the needs of one-step affinity purification.

(3) Highly efficient and stable cell lines can be produced and characterized, which is suitable for large-scale fermentation production.


2.Stable Gene Expression.

Stable gene expression meets the needs of long-term production and the entire stable transfection and screening process provides long -term stability and scale-adjustable protein production.


3.Transient Gene Expression (TGE)

(1) Compared with stable gene expression, TGE is mainly suitable for the preparation of recombinant protein

in a short period of time, which can be rapidly transfected within 10 days without genetic selection of plasmid DNA.

(2) The transient expression of AtaGenix uses suspension cells with volumes ranging from milliliters to 100L.


4.Process Development and Scale-up. AtaGenix can optimize the expression process and its product, predict the cell expression amount, and find out the fermentation conditions of fermentation tanks, which is suitable for large-scale fermentation production.


5. Purification. AtaGenix has a complete protein purification system, affinity purification, gel filtration, ion exchange and hydrophobic chromatography purification methods, which can complete the purification of various types of proteins, as well as the purification process mapping.


AtaGenix provides one-stop protein technology services such as expression vector construction, instant transfection, expression testing, large-scale animal cell fermentation and protein purification.

Expression Methods

Cell Lines



Transient Expression


HEK293 cells are derived from the 293 cell line and adapted in suspension with serum-free media.


CHO-S cells are clonal isolates from Chinese hamster ovary cells adapted to serum-free suspension culture


Stable Expression


CHO-K1 is derived from CHO, a cell line with simple culture.

conditions and moderate adherence strength, which is relatively easy to transfect.



Stable Cell Line Construction


DG44 cells (dihydrofolate reductase deficient, DHFR-) are derived from Chinese hamster ovary (CHO) cells and are commonly used to construct cell lines suitable for recombinant protein production. DG44 cell selection and co-amplification marker is the DHFR gene.

Expression Vectors: pcDNA3.1, pIRES, pTT3, pCEP4, and pATX1, etc.


Experienced Team: 10 years+ experience in protein expression,5000+ mammalian expression projects and 500+ stable cell line construction projects.

Various expression services available: transient transfection expression, recombinant antibody expression production, and stable cell line construction services.

1.Transient Expression: A variety of mammalian cell expression systems cultured without serum, independent research and development of high-yield expression systems, greatly increase the expression (3-6 times),while providing commercial transfection system for customers.

2. Recombinant Antibody Expression: With a set of proven vector-cell transfection high-efficiency

expression system, short-term, large-scale production of recombinant antibodies above the g level.

3. Construction of Stable Cell Lines: CHO-K1 modified cell lines with independent intellectual

property rights, ideal for mass production of protein, antibody drugs and other industrial-grade raw


4.Class 100,000 Clean Room for Cell Culture : endotoxin level <0.1EU/ml.

5. Large Scale Productions: 200L+ production per batch of serum-free suspension cell culture.

6. One-stop Service: Gene optimization, protein structure analysis and expression design, transient

transfection, stable cell line construction, recombinant antibody production, and data analysis.





Time Frame





Mammalian expression system




Gene sequence or vector

Gene synthesis

2-4 weeks

Gene synthesis reports

Pilot expression & purification test

2 weeks

Expression & purification test reports

1L expression & purification

2 weeks

Protein samples & reports

Shake flask or

bioreactor scale up

2-4 weeks

Protein samples & reports


Case Study

Transient expression of viral transmembrane glycoprotein RG in HEK293 cells.