The DUSP28 Knockout HAP1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population produced from the HAP1 human near-haploid cell line. This product has been engineered to disrupt the DUSP28 gene, establishing a loss-of-function model for analyzing the regulatory functions of this dual specificity phosphatase in stress-activated MAPK signaling. The polyclonal nature captures the heterogeneity of gene-editing outcomes within the population, making it well-suited for robust functional studies without the bias of single-clone selection.
The HAP1 host cell line is a human near-haploid chronic myeloid leukemia (CML) cell line, originally derived from KBM-7. It maintains a near-haploid karyotype and expresses the BCR-ABL1 fusion protein, a hallmark of CML. Because most genes are present as single alleles, HAP1 cells are an ideal platform for haploid genetic screens and loss-of-function studies. This genetic simplicity facilitates unambiguous knockout phenotypes, providing a clear background for investigating gene function in signaling and disease contexts.
DUSP28 is a dual specificity phosphatase that dephosphorylates tyrosine and threonine residues, primarily targeting the stress-activated MAP kinases p38 and JNK. It functions as a negative feedback regulator, directly binding and inactivating these kinases in response to oxidative stress and pro-inflammatory cytokines such as TNF-?? and IL-1??. Within the MAPK cascade, upstream MAP3Ks (e.g., ASK1, MEKK1) activate MAP2Ks (MKK3/6, MKK4/7), which phosphorylate p38 and JNK. These kinases then phosphorylate transcription factors ATF2 and c-Jun to induce stress-responsive genes. DUSP28 attenuates this signaling by dephosphorylating p38 and JNK, thereby modulating cellular survival, apoptosis, and inflammatory responses.
In the haploid HAP1 background, CRISPR/Cas9-mediated disruption of the single DUSP28 allele leads to complete loss of protein expression, resulting in a clean loss-of-function system. This genetic context amplifies the phenotypic outcomes of DUSP28 deficiency, particularly evident in stress-induced MAPK activation assays. For example, upon stimulation with anisomycin or cytokines, DUSP28 knockout cells exhibit sustained p38 and JNK phosphorylation compared to wild-type controls. The BCR-ABL1-positive background further permits exploration of phosphatase involvement in CML signaling, where MAPK pathways influence proliferation and drug resistance.
These polyclonal knockout cells are suitable for diverse applications including phospho-p38 and phospho-JNK western blotting, AP-1 luciferase reporter assays, and cytokine ELISAs. Cell viability and apoptosis assays under stress can assess DUSP28 function. RNA-seq and phosphoproteomics enable systems-level pathway analysis. The haploid background also facilitates genetic modifier screens. These cells are a versatile tool for functional genomics, drug target validation, and phosphatase research in cancer and inflammation. For ordering or technical inquiries, please contact Ascent Research.
