The HTR3B Knockout HAP1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population designed to study the 5-HT3B subunit of the serotonin 5-HT3 receptor. These cells, derived from the near-haploid human HAP1 cell line, contain a targeted disruption of the HTR3B gene, providing a loss-of-function model for functional genomic and pharmacological investigations. The targeted disruption abolishes expression of the full-length 5-HT3B protein, enabling unambiguous phenotypic analyses.
HAP1 is a male human near-haploid fibroblast-like cell line originating from the KBM-7 chronic myeloid leukemia line. It is haploid for most chromosomes except a disomic segment on chromosome 15. This karyotype permits efficient CRISPR-mediated gene disruption, as a single editing event yields a uniform knockout allele, making HAP1 a preferred model for knockout validation and functional screens.
The HTR3B protein co-assembles with the 5-HT3A subunit to form a heteromeric ligand-gated cation channel. Upon activation by serotonin or agonists such as 2-methyl-5-HT, the channel conducts Na+ and Ca2+, leading to membrane depolarization and neurotransmitter release including dopamine and acetylcholine. The 5-HT3B subunit is chaperoned by RIC-3, which is essential for proper folding and cell surface expression of the receptor complex. It also interacts with tissue-specific subunits (5-HT3C/D/E). Antagonists like ondansetron and granisetron inhibit channel function. Additional pathway components include the serotonin transporter SLC6A4.
Knocking out HTR3B in the haploid HAP1 background removes the modulatory 5-HT3B subunit without residual wild-type copies, enabling clear functional analyses. This model is valuable for dissecting receptor assembly, trafficking, and stoichiometry, as well as screening for subunit-specific compounds. The simplified genetics facilitate robust interpretation of pharmacological and electrophysiological data.
Researchers can employ these cells in patch clamp electrophysiology, calcium imaging with Fluo-4, and radioligand binding with [3H]granisetron to characterize channel properties. Co-immunoprecipitation with 5-HT3A probes subunit interactions, while flow cytometry assesses surface receptor expression. Ondansetron sensitivity assays and sequencing-based knockout validation are also supported. This polyclonal knockout product is a versatile tool for serotonin receptor biology, antiemetic drug discovery, and ion channel research. For further information or custom cell line engineering, please contact Ascent Research.
