CHOZN® ZFN-Modified DHFR-/- CHO Cell Line DHFR敲除的CHO悬浮高效表达细胞株 BioVector NTCC质粒载体菌种细胞基因保藏中心

CHOZN® ZFN-Modified DHFR-/- CHO Cell Line DHFR敲除的CHO悬浮高效表达细胞株

The CHOZN ZFN-Modified DHFR-/- CHO cell line was created
using BioVector NTCC Inc. proprietary CompoZr® zinc finger nuclease
(ZFN) technology. ZFNs are a class of engineered DNA-binding
proteins, which facilitate targeted genome editing by binding
to a user-specified locus and causing a double-strand
break (DSB). The cell then employs endogenous DNA repair
processes, either non-homologous end joining (NHEJ) or
homology-directed repair (HDR), to heal this targeted DSB.
These repair processes can be channeled to generate precisely
targeted genomic edits resulting in an organism or cell lines with
specific gene disruptions (knockouts), integrations, or modifications.
The dihydrofolate reductase (DHFR) protein catalyzes the
reduction of 5,6-dihydrofolate to 5,6,7,8-tetrahydrofolate, an
essential step in purine metabolism. Cells lacking a functional
copy of the DHFR gene must be grown in culture medium
supplemented with the purine precursors hypoxanthine and
thymidine (HT). This metabolic selection process can be
used to select for cells that have been transfected with a
gene(s) of interest for recombinant protein expression along
with an exogenous copy of the DHFR gene. Methotrexate
(MTX) strengthens the selection process by inhibiting DHFR
activity, thereby pushing the cells to express more DHFR and
consequently more recombinant protein, presumably through
gene amplification. Currently, the biopharmaceutical industry
uses DuxB11 and DG44 host cells for DHFR selection of
recombinant cell lines. In DG44 cells, both copies of the DHFR
gene non-functional, enabling strong metabolic selection
of recombinant cell lines. DuxB11 cells, however, have one
functional and one-non functional copy of the DHFR gene.
Therefore, DHFR metabolic selection strategies for recombinant
cell line are less effective when using this host. These traditional
DHFR deficient cell lines display some unfavorable growth
and handling characteristics. They are known to be difficult to
adapt to serum-free suspension growth conditions, and tend to
be very clumpy in shaken cultures. For these reasons, SAFC
developed a more robust, user friendly CHO DHFR deficient
host cell line. Using the ZFN technology, SAFC has engineered
a novel CHO K1 DHFR-/- cell line. This CHOZN DHFR null cell
line is adapted to chemically-defined, suspension growth in
EX-CELL CD CHO Fusion media (SAFC Cat. No. 14365C) and
maintains many of the robust characteristics of CHO K1.

Supplier来源:BioVector NTCC Inc.
TEL电话:400-800-2947
Website网址: http://www.biovector.net