PDE4D Knockout Raji Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population designed for targeted disruption of the PDE4D gene in the human Raji B lymphocyte cell line. This gene-edited pool provides a loss-of-function model of phosphodiesterase 4D, enabling researchers to investigate cAMP-dependent signaling without introducing artifacts from clonal selection. The polyclonal format captures a broad representation of editing events across the population, making it suitable for bulk functional analyses where average gene-disruption effects are desirable. By eliminating PDE4D enzymatic activity, these cells facilitate dissection of the phosphodiesterase??s role in modulating second messenger pathways central to lymphocyte biology.
Raji cells are an Epstein-Barr virus (EBV)-positive lymphoblastoid line originally derived from a Burkitt??s lymphoma patient. They exhibit characteristic features of mature B lymphocytes, including robust antibody production and antigen-presentation capacity, and are widely employed as a model system for B cell malignancies and immune function. The EBV-immortalized state supports stable propagation and reproducible experimental outcomes, while retaining key B cell receptor signaling machinery. This background makes Raji cells particularly valuable for examining the intersection of oncogenic transformation, viral latency, and normal B cell physiology, especially in the context of cAMP-regulated processes.
PDE4D encodes a cAMP-specific phosphodiesterase that catalyzes hydrolysis of the second messenger cAMP to AMP, thereby attenuating downstream signaling. Its activity is modulated by upstream inputs such as beta-adrenergic agonists and GPCR ligands, and it is regulated by PKA-mediated phosphorylation and CREB-dependent transcription. PDE4D physically interacts with scaffold proteins including A-kinase anchoring proteins (AKAPs), beta-arrestin, receptor for activated C-kinase 1 (RACK1), and phosphodiesterase 4D-interacting protein (PDE4DIP)/myomegalin, which spatially compartmentalize its function. Within the cAMP signaling network, PDE4D functions upstream of PKA and EPAC, controlling phosphorylation of CREB and activation of NF-??B, as well as modulating ion channel activity and gene expression programs such as IL-2 and NFAT. The polyclonal knockout disrupts this critical node, leading to elevated basal and stimulated cAMP levels.
In Raji B cells, PDE4D knockout is expected to enhance PKA activity and CREB phosphorylation, potentially altering B cell receptor signaling, proliferation, and cytokine output. This model enables investigation of how localized cAMP pools, organized by AKAP complexes, govern lymphocyte activation and differentiation. It also provides a physiologically relevant system to study phosphodiesterase contributions to EBV-driven lymphomagenesis and immune evasion. The polyclonal nature ensures that the resultant phenotype reflects the average effect of PDE4D loss across a diverse edited population, minimizing clonal bias while maintaining a robust knockout representation.
This product supports a wide range of applications, including mechanistic studies of GPCR?CcAMP?CPKA axis in B cells, screening and characterization of PDE4 inhibitors such as rolipram, and functional validation of PDE4D as a therapeutic target in lymphomas. Representative assays compatible with these cells include intracellular cAMP measurement via ELISA or FRET-based reporters, western blotting for PDE4D and downstream phospho-targets (e.g., phospho-CREB, PKA substrates), RT-qPCR for CREB-regulated genes, flow cytometric analysis of B cell activation markers (CD69, CD86), and cell proliferation assays (MTT, BrdU). Drug sensitivity testing with PDE4 inhibitors can be performed to assess synergy with existing therapies. For additional information or technical support, please contact Ascent Research.
