CD Biosynsis offers high-efficiency CHO (Chinese Hamster Ovary) Cells Multi-Gene Knockout Strain Construction Services, providing permanent and precise deletion or disruption of multiple target genes in this premier mammalian host. CHO cells are the industry workhorse for producing complex biotherapeutics, including monoclonal antibodies (mAbs). Multi-gene knockout is a critical step in advanced host cell engineering, utilized primarily to systematically eliminate multiple competing pathways, remove redundant product-degrading proteases, or fully disrupt complex native glycosylation pathways (e.g., removing all fucosylation enzymes). Leveraging the precision of multiplex CRISPR-Cas9 to induce simultaneous double-strand breaks (DSBs), our services rely on the cell's Non-Homologous End Joining (NHEJ) pathway to generate stable, multi-allelic, loss-of-function mutations. We accelerate the development of superior CHO cell lines with enhanced viability, productivity, and tailored product quality.
Get a QuoteAchieving multiple gene knockouts in CHO cells is complex due to the host's pseudo-tetraploid genome, requiring disruption of multiple alleles across several genes. Our platform is optimized to address this by focusing on high-efficiency, transient delivery of the editing machinery (RNP) and the use of multiplex gRNA arrays. This ensures that multiple DSBs are created simultaneously at different loci. The repair via the error-prone NHEJ pathway generates frameshift mutations (indels) that functionally disrupt the genes in a single step. This strategy is critical for engineering complex traits, such as creating a stable triple-protease knockout strain or a fully fucosylation-deficient host.
gRNA Array Design
Rational design of multiple guide RNAs (gRNAs) simultaneously targeting the early coding region of 2 to 5 genes to maximize the chance of multi-allelic, frame-shift mutations via NHEJ.
Single vs. Sequential Knockout
Strategy optimization based on gene essentiality; performing simultaneous knockouts for non-essential targets (e.g., proteases) or sequential editing for lethal/complex pathway deletions.
Allelic Verification Primers
Design of robust primers for rapid screening and clone-level verification of successful indel formation in all functional alleles of all targeted genes using TIDE or Sanger sequencing.
RNP Delivery System
Preference for Ribonucleoprotein (RNP) delivery for transient, high-efficiency, and low off-target activity, critical for safety and speed in the CHO cell host.
Pol III Multiplex Cassettes
Construction of Pol III promoter-driven gRNA expression cassettes (e.g., U6/H1) to ensure robust, simultaneous expression of all gRNAs necessary for multi-locus cleavage.
Selection Marker Strategy
Use of co-transfected selection markers or integrated markers to enrich for the cell population that has undergone the desired, rare multi-gene editing event.
Glycoengineering (Fucosylation KO)
Simultaneous deletion of FUT8 and other fucosylation genes to produce afucosylated antibodies, enhancing therapeutic efficacy (ADCC activity).
Protease System Disruption
Deletion of multiple host cell proteases (e.g., Cathepsin L and other critical proteases) to eliminate product degradation and ensure high integrity of the secreted mAb.
Apoptosis & Metabolism Engineering
Combined knockout of pro-apoptotic genes (e.g., Bax/Bak) and metabolic shunts (e.g., lactate pathway component) to maximize cell viability and carbon flux for titer.
A systematic process for achieving multiplex disruption and stable clone isolation.
1. Multiplex Design & RNP Preparation
2. Transfection & Multi-Locus Editing
3. Single Cell Cloning & Screening
4. Clone Verification & Delivery
Identify all target genes (2+ loci). Design and synthesize the multiplex gRNA array targeting all loci simultaneously.
Prepare the Cas9 enzyme/multiplex gRNA Ribonucleoprotein (RNP) complex for transient, high-efficiency delivery.
Design multi-locus verification strategy (e.g., multiplex PCR, TIDE sequencing).
Deliver the RNP complex (and selection marker if required) into the CHO host cell line via optimized electroporation.
Culture cells to allow the NHEJ repair pathway to finalize the genomic edit at all targeted loci.
Apply antibiotic selection or FACS sorting to enrich for edited clones with high editing frequency.
Genotype verification via TIDE/Sanger sequencing of all target loci to confirm indel formation in all alleles of every targeted gene.
Phenotypic validation of the final clone for multi-gene function and long-term stability.
Delivery of the verified CHO master cell bank (MCB) and comprehensive documentation.
Multiplex RNP Efficiency
Use of multiplex RNP delivery achieves simultaneous disruption of multiple genes in a single transfection step, dramatically accelerating the complex chassis engineering timeline.
Multi-Allelic Disruption
Strategies are optimized to ensure all functional alleles across multiple loci are disrupted, providing complete loss-of-function phenotypes (e.g., full fucosylation knockout).
Enhanced Product Quality Control
Enables the systematic removal of entire degradation systems (multiple proteases) and native glycosylation pathways for superior product integrity and tailored glycoprofiles.
Rapid Clonal Isolation
Integration of HTS and automated single-cell cloning rapidly isolates rare, multi-edited clones, shortening the development timeline required to establish the Master Cell Bank (MCB).
1. How do you ensure knockout of all alleles across multiple genes simultaneously?
We use a high concentration of the multiplex RNP complex to saturate the cells and generate simultaneous DSBs at all targeted sites. Clones are then extensively screened via sequencing (TIDE) to confirm disruptive indels in all alleles of every targeted gene.
2. What is the role of NHEJ in multi-gene knockout?
NHEJ (Non-Homologous End Joining) is the primary repair pathway used for knockouts. It is error-prone, meaning it generates frame-shift mutations (indels) when repairing the simultaneous Cas9 cuts, thus functionally disrupting multiple genes at once.
3. Why is multi-gene knockout necessary for glycoengineering (e.g., afucosylation)?
To eliminate a function like core fucosylation, all functional alleles of the key enzyme, such as FUT8, must be completely disrupted. For full control, other related enzymes may also need to be knocked out, necessitating a multi-gene approach.
4. What types of protease genes are commonly targeted for multi-knockout?
We typically target key host cell proteases (HCPs) known to degrade secreted proteins, including Cathepsin L (CTSL) and other secreted proteases that cleave the target mAb, ensuring maximal product integrity.
5. How is the final multi-gene knockout clone verified?
Verification is comprehensive: it includes multiplex PCR to confirm overall locus disruption, TIDE/Sanger sequencing of every allele for all targeted genes, and functional assays to confirm the desired phenotype (e.g., loss of fucosylation activity).
6. Can you combine multi-gene knockout with gene knock-in in one project?
Yes. A common strategy is to perform the multi-gene knockout (e.g., proteases) first to create the optimized chassis, and then use a subsequent CRISPR/HDR step to perform a high-titer gene knock-in (e.g., the therapeutic mAb) into a safe harbor locus.
7. What input is required to start a multi-gene knockout project?
We require the specific CHO host cell line and a prioritized list of 2 or more genes (locus tags or sequences) targeted for complete functional disruption, along with the desired final product.
8. What is the biggest challenge in CHO multi-gene knockout?
The biggest challenge is verifying the homozygous disruption of all functional alleles across multiple targeted loci due to the complex CHO pseudo-tetraploid genome. Our rigorous sequencing and screening methods are designed to overcome this complexity.
CRISPR-Cas9 technology represents a transformative advancement in gene editing techniques. The main function of the system is to precisely cut DNA sequences by combining guide RNA (gRNA) with the Cas9 protein. This technology became a mainstream genome editing tool quickly after its 2012 introduction because of its efficient, simple and low-cost nature.
The CRISPR gene editing system with its Cas9 version stands as a vital instrument for current biological research. CRISPR technology enables gene knockout (KO) through permanent gene expression blockage achieved by sequence disruption. Various scientific domains including disease modeling and drug screening employ this technology to study gene functions. CRISPR KO technology demonstrates high efficiency and precision but requires confirmation and verification post-implementation because unsatisfactory editing may produce off-target effects or incomplete gene knockouts which impact experimental result reliability. For precise and efficient Gene Editing Services - CD Biosynsis, Biosynsis offers comprehensive solutions tailored to your research needs.
The CRISPR-Cas9 knockout cell line was developed using CRISPR/Cas9 gene editing to allow scientists to remove genes accurately for research on gene function and disease models and pharmaceutical discovery. Genetic research considers this technology essential due to its high efficiency together with simple operation and broad usability.
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