The CBX3 Knockout K-562 Polyclonal Cells product provides a CRISPR/Cas9-edited polyclonal population of K-562 human chronic myelogenous leukemia cells harboring targeted disruption of the CBX3 gene. This polyclonal knockout cell pool avoids the need for single-cell cloning, enabling robust loss-of-function studies in a heterogeneous genetic background. The population-level gene inactivation delivers a practical model system for investigating HP1??-mediated processes in pooled screens and bulk assays.
The host K-562 cell line was established from the pleural effusion of a 53-year-old female with CML in blast crisis. K-562 cells carry the Philadelphia chromosome and express the BCR-ABL1 fusion oncoprotein, driving constitutive tyrosine kinase signaling and uncontrolled proliferation. As a widely utilized model, K-562 recapitulates features of myeloid leukemia and serves as a platform for studying hematopoietic differentiation, epigenetic regulation, and drug resistance mechanisms.
CBX3 (HP1??) is a chromodomain protein that binds H3K9me3 marks to enforce heterochromatin formation and transcriptional repression. It interacts with histone methyltransferases SUV39H1/SUV39H2, DNMT3A, and the NuRD complex, and dimerizes with HP1 family members CBX1 and CBX5. Activity is regulated by AURKA and CDK1 phosphorylation, SUMOylation, and ATM/ATR signaling upon DNA damage. CBX3 represses CDKN1A and MYC transcription while promoting erythroid genes GATA1 and GYPA, thereby linking heterochromatin maintenance to cell cycle control and differentiation.
In the K-562 leukemic background, BCR-ABL1 signaling influences heterochromatin organization, and disruption of CBX3 may upset this equilibrium, leading to derepression of targets such as MYC and altered DNA damage responses through ATM/ATR pathways. Loss of CBX3 function can impair differentiation and modulate sensitivity to tyrosine kinase inhibitors like imatinib. This polyclonal knockout model thereby facilitates exploration of how epigenetic dysregulation contributes to CML progression and drug resistance, mirroring clonal heterogeneity seen in advanced disease.
Typical applications include western blotting and immunofluorescence for CBX3 and H3K9me3, RT-qPCR of downstream targets (CDKN1A, MYC, BCL2, GATA1), ChIP-qPCR for H3K9me3 occupancy, and flow cytometry for cell cycle and apoptosis. Colony formation assays with imatinib gauge drug sensitivity. This product is ideal for CRISPR screen validation, epigenetic drug target identification, and myeloid differentiation research. For additional details, contact Ascent Research.
