BPHL Knockout HAP1 Polyclonal Cells constitute a CRISPR/Cas9-mediated polyclonal knockout population targeting the human BPHL gene in the HAP1 near-haploid cell line. This gene-edited pool, generated by CRISPR/Cas9 disruption of the BPHL locus, serves as a powerful loss-of-function model for investigating valacyclovir prodrug activation and related xenobiotic metabolism pathways. The polyclonal format provides a heterogeneous knockout population, reflecting diverse editing events across the cell pool, and is suitable for pooled functional assays where monoclonal isolation is not required.
The HAP1 host cell line is an adherent near-haploid human cell line originally derived from the KBM-7 chronic myeloid leukemia line. HAP1 cells contain a single copy of most chromosomes, eliminating confounding effects of heterozygous loci and enabling straightforward generation of complete gene knockouts. Their haploid genome facilitates the production of loss-of-function models even for essential genes, and the line’s rapid proliferation and robust experimental tractability make it a widely adopted system for CRISPR-based functional genomics, drug screening, and genetic interaction studies.
BPHL encodes a serine hydrolase that catalyzes the hydrolytic activation of the antiviral prodrug valacyclovir to acyclovir, the active agent against herpesviruses. This enzyme also possesses arylacetamide deacetylase activity and functions in xenobiotic metabolism. Expression of BPHL is potentially regulated by xenobiotic-responsive nuclear receptors such as PXR and CAR. Mechanistically, BPHL directly hydrolyzes the ester-linked valine moiety of valacyclovir, producing acyclovir, which then acts downstream as a viral DNA polymerase inhibitor. Interacting factors include valacyclovir and other arylacetamide substrates, positioning BPHL as a critical node in prodrug activation and drug metabolism pathways.
In the HAP1 background, BPHL knockout abrogates the conversion of valacyclovir to acyclovir, creating a clean null model for dissecting prodrug pharmacokinetics independent of hepatic enzyme contributions. The near-haploid genome ensures that residual wild-type BPHL activity is absent, enabling unambiguous assessment of the enzyme’s role in drug activation and metabolism. This model is particularly valuable for pharmacogenetic studies, as it can be used to mimic loss-of-function variants that influence valacyclovir efficacy in patients. Moreover, the knockout cells can be complemented with mutant BPHL constructs to explore structure-function relationships and substrate specificity.
Research applications for BPHL Knockout HAP1 Polyclonal Cells encompass a wide range of functional assays. Researchers can perform valacyclovir hydrolysis enzyme assays to quantify loss of prodrug activation, LC-MS/MS measurement of acyclovir production to confirm metabolic blockage, and cell viability assays under valacyclovir challenge to assess functional outcomes. Additional applications include Western blotting and RT-qPCR for validation of BPHL disruption and off-target screening, as well as RNA-seq transcriptomic analysis to explore global metabolic adaptations. These cells are suited for antiviral pharmacology, prodrug activation studies, and drug metabolism research. For further technical details, please contact Ascent Research.
