The ABCD4 Knockout HT29 Polyclonal Cells represent a heterogeneous CRISPR/Cas9-edited HT29 cell population harboring targeted disruption of the ABCD4 locus. This polyclonal knockout model is designed to abolish functional expression of the ABCD4 ATP-binding cassette transporter, enabling loss-of-function studies in a physiologically relevant colorectal adenocarcinoma background. The product is supplied as a viable, early-passage polyclonal pool that supports robust experimental scalability and flexible downstream analytical workflows, including immunoblotting, uptake assays, and metabolomic profiling, without the necessity of isolating single-cell clones.
HT29 is a well-characterized human colorectal adenocarcinoma cell line exhibiting epithelial morphology and harboring heterozygous mutations in APC, TP53, and KRAS. Originating from a primary tumor, HT29 cells are capable of enterocytic differentiation and mucus production under defined culture conditions, making them a versatile platform for investigating intestinal epithelial biology and oncogenic signaling. Their genetic background, particularly the constitutively active KRAS and dysfunctional p53, provides a tumorigenic context in which metabolic reprogramming and nutrient-sensing pathways can be interrogated, while their differentiation capacity allows exploration of gene function in both progenitor and differentiated states.
ABCD4 encodes a lysosomal membrane protein that functions as a putative ATP-binding cassette transporter mediating the efflux of cobalamin (vitamin B12) from the lysosomal lumen into the cytoplasm. Functioning downstream of receptor-mediated endocytosis and lysosomal processing of transcobalamin-II-bound cobalamin, ABCD4 cooperates with LMBD1 and the MMACHC?CMMADHC complex to facilitate cytoplasmic delivery of the cofactor. In the cytoplasm, cobalamin is converted to methylcobalamin, the cofactor for methionine synthase (MTR), and adenosylcobalamin, required for methylmalonyl-CoA mutase (MMUT). Disruption of ABCD4 traps vitamin B12 within lysosomes, impairing MTR and MMUT activities, which leads to accumulation of homocysteine and methylmalonic acid and disrupts one-carbon metabolism. Expression of ABCD4 is regulated by TFEB, the master transcriptional controller of lysosomal biogenesis, and is responsive to nutrient-sensing pathways and lysosomal stress signals.
In the HT29 background, ABCD4 loss creates a powerful model to dissect cobalamin-dependent metabolic vulnerabilities in colorectal cancer. The adenocarcinoma origin, combined with the interplay of oncogenic drivers such as mutant KRAS, permits investigation into how impaired one-carbon metabolism influences nucleotide biosynthesis, redox balance, and epigenetic regulation in a tumorigenic context. Furthermore, because HT29 cells can differentiate into enterocyte-like and goblet cell-like phenotypes, the ABCD4 knockout enables studies of vitamin B12 trafficking during intestinal epithelial differentiation and may reveal context-dependent roles of lysosomal cobalamin export in cellular maturation and function.
This polyclonal knockout product is suited for a wide range of research applications, including mechanistic dissection of intracellular cobalamin trafficking, functional modeling of cblJ-type methylmalonic aciduria and homocystinuria, and exploration of lysosomal storage-like defects. Researchers can employ western blotting and immunofluorescence to verify ABCD4 ablation and assess lysosomal localization, cobalamin uptake assays to quantify transport defects, and LC-MS to monitor homocysteine and methylmalonic acid accumulation. Proliferation assays under vitamin B12 restriction and LysoTracker-based lysosomal function analyses further enable metabolic phenotyping, while RT-qPCR confirms target disruption. The ABCD4 Knockout HT29 Polyclonal Cells thus provide a versatile and technically accessible platform for probing the intersection of lysosomal biology, one-carbon metabolism, and colorectal cancer. For further information, contact Ascent Research.
