The C1QA Knockout HEK293T Polyclonal Cells product consists of a CRISPR/Cas9-edited polyclonal knockout cell population targeting the human C1QA gene in HEK293T cells. This heterogeneous pool of edited cells provides a loss-of-function model for the A-chain of complement C1q, enabling investigation of classical complement pathway initiation and associated cellular processes. The polyclonal format allows researchers to study population-level responses without clonal selection, reflecting a broader range of genetic backgrounds.
HEK293T cells are a widely used human embryonic kidney cell line transformed with adenovirus 5 DNA and stably expressing the SV40 large T antigen. These cells serve as a robust platform for high-level protein expression and lentiviral/retroviral production due to their high transfection efficiency and rapid proliferation. The well-characterized genetic background facilitates reproducible experimental outcomes, making this line an ideal host for generating C1QA knockout models for complement research in a non-immune cell context.
C1QA encodes the A-chain of C1q, a subunit of the C1 complex that initiates the classical complement pathway. C1q functions as a pattern recognition molecule, binding to immune complexes (IgG, IgM) and apoptotic cell-associated ligands such as calreticulin. This recognition triggers activation of the associated serine proteases C1r and C1s, leading to cleavage of downstream components C4 and C2 to form the C3 convertase (C4b2a), subsequently promoting opsonization, inflammation, and clearance of apoptotic debris. C1QA expression is regulated by transcription factors including PU.1, and by cytokines such as interferon-gamma and macrophage colony-stimulating factor, linking complement activity to immune cell development and activation. This model disrupts C1q A-chain production, preventing functional C1 complex assembly and blocking downstream classical complement signaling.
In the HEK293T context, C1QA knockout cells offer a unique tool for dissecting complement-mediated mechanisms independent of immune cell-specific factors. HEK293T cells do not normally express components of the complement cascade, making this an engineered system for reconstitution studies. By reintroducing wild-type or mutant C1QA constructs, researchers can examine structure-function relationships, protein-protein interactions (e.g., with C1r, C1s, or CD91/LRP1), and the biochemical requirements for C1 complex formation. The platform supports high-throughput screening approaches to identify modulators of C1q-mediated phagocytosis or synaptic pruning, relevant to neurodegenerative diseases.
This knockout model is particularly suited for research into autoimmune diseases such as systemic lupus erythematosus (SLE), where C1q deficiency is strongly linked to impaired immune complex clearance, and for studying complement dysfunction in age-related macular degeneration and Alzheimer??s disease. Key applications include the study of complement-mediated immunity using hemolytic complement assays (CH50), ELISA-based functional C1q assays, and flow cytometric analysis of C1q binding to apoptotic cells. The cells also enable drug screening for complement inhibitors targeting the C1 complex. For additional technical details or ordering information, please contact Ascent Research.
