The IPO4 Knockout HT29 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population in which the IPO4 gene has been disrupted in the HT29 human colorectal adenocarcinoma cell line. This loss-of-function model enables the study of IPO4-dependent nuclear import and its functional roles in cellular homeostasis and disease. The polyclonal nature offers a heterogeneous pool of edited cells, providing a robust system for population-level analyses of nuclear import defects and their downstream consequences.
HT29 is a human colorectal adenocarcinoma cell line established from a 44-year-old Caucasian female. These adherent epithelial cells are widely used to model intestinal barrier function and colorectal cancer biology. They form polarized monolayers with tight junctions, enabling transepithelial electrical resistance (TEER) measurements to assess barrier integrity. HT29 cells carry mutations in APC and TP53, reflecting the genetic landscape of colorectal tumors, and are thus highly relevant for studying cancer progression and drug permeability in an epithelial context.
IPO4 encodes importin-4, an importin-?? family nuclear transport receptor that mediates RanGTP-dependent nuclear import of NLS-containing cargoes, including ribosomal proteins RPL23A and RPS7, and the DNA damage factor 53BP1. It also participates in mitotic spindle assembly. IPO4 is regulated by RanGTPase and nucleoporins, and its expression is controlled by E2F and c-Myc downstream of mTOR and cell cycle regulators. Disruption of IPO4 impairs nuclear import of multiple cargoes, linking it to ribosome biogenesis, p53 signaling, and DNA damage repair.
In HT29 colorectal cancer cells, IPO4 knockout provides a physiologically relevant model of defective nuclear import in a hyperproliferative epithelial background. Cancer cells often upregulate ribosome biogenesis; loss of IPO4 may reduce nuclear delivery of ribosomal proteins, potentially suppressing ribosome assembly and protein synthesis. Impaired nuclear translocation of 53BP1 could compromise DNA double-strand break repair, increasing sensitivity to genotoxic agents??a therapeutically relevant phenotype. The HT29 epithelial barrier model further permits investigation of how nuclear transport defects affect tight junction formation and monolayer integrity, while also serving as a platform for studying viral nuclear entry mechanisms in colorectal epithelia.
Researchers can assess IPO4 knockout using immunofluorescence for cargo mislocalization (e.g., RPL23A, 53BP1), western blotting and RT-qPCR for expression analysis, and cell cycle flow cytometry. ??-H2AX foci assays evaluate DNA damage response, TEER measurements monitor barrier integrity, and migration assays assess metastatic potential. These cells support research in nuclear transport, ribosome biogenesis, DNA repair, colorectal cancer progression, and drug permeability. Contact Ascent Research for more information.
