This CRISPR/Cas9-edited polyclonal knockout cell population lacks functional GSTZ1 expression. The polyclonal pool, derived from the HAP1 cell line, provides a heterogeneous loss-of-function model suitable for pooled analysis of GSTZ1-dependent processes. Gene disruption eliminates GSTZ1 activity, blocking the penultimate step of tyrosine catabolism. This knockout model enables systematic investigation of GSTZ1’s role in metabolic detoxification and its relevance to human disease.
HAP1 is a human near-haploid cell line originally derived from the chronic myeloid leukemia KBM-7 line. It grows in suspension and maintains a stable haploid karyotype, making it highly tractable for functional genomics, including CRISPR-based screens and targeted gene editing. As a leukemia-derived model, HAP1 cells recapitulate aspects of hematopoietic malignancy while offering simplified genetic manipulation. The near-haploid genome minimizes confounding effects of heterozygous mutations, facilitating clean genotype-phenotype correlations in knockout studies.
GSTZ1 catalyzes the glutathione-dependent isomerization of maleylacetoacetate to fumarylacetoacetate, the penultimate step of tyrosine degradation. It also exhibits dehalogenase activity toward dichloroacetate. Expression is regulated by transcription factors NRF2 and HNF4A, and modulated by glucagon and insulin. Downstream, fumarylacetoacetate is hydrolyzed by FAH to fumarate and acetoacetate, which enter the TCA cycle. Disruption leads to accumulation of maleylacetoacetate and homogentisate, inducing oxidative stress and mitochondrial dysfunction.
In the HAP1 leukemia background, loss of GSTZ1 impairs tyrosine catabolic capacity, forcing reliance on alternative metabolic routes. This metabolic inflexibility may increase sensitivity to oxidative stress and alter drug responses, particularly to agents like dichloroacetate that require GSTZ1-mediated detoxification. The model thus provides a relevant system for studying how tyrosine metabolism intersects with cancer cell survival and drug metabolism. The near-haploid nature of HAP1 cells further simplifies studying downstream metabolic consequences without compensatory gene copies.
This polyclonal knockout population suits diverse workflows: LC-MS metabolomics, glutathione depletion, ROS detection, and viability under tyrosine challenge. It models tyrosinemia type I-like disruptions and evaluates dichloroacetate toxicity in leukemia. Applications include functional genomics, drug sensitivity profiling, and mechanistic studies of metabolic acidosis and hepatocellular carcinoma. For technical support, contact Ascent Research.
