The HPRT1 Knockout HT29 Polyclonal Cells comprise a CRISPR/Cas9-edited polyclonal knockout cell population in which the hypoxanthine-guanine phosphoribosyltransferase 1 (HPRT1) gene has been disrupted across a heterogeneous pool of human HT29 colorectal adenocarcinoma cells. This polyclonal architecture avoids clonal drift and provides a robust loss-of-function model for studying purine salvage pathway dynamics within a genetically diverse epithelial tumor background. The knockout population was generated using a CRISPR/Cas9-mediated gene disruption strategy that targets the HPRT1 locus, yielding a mixed population suitable for applications requiring stable abrogation of HPRT1 activity without the confounding effects of single-cell selection.
HT29 is a widely characterized human colorectal adenocarcinoma epithelial cell line originally isolated from a primary tumor of a 44-year-old female patient. It serves as a canonical intestinal epithelial model due to its ability to form polarized monolayers and to differentiate into mucin-producing and absorptive cell types under appropriate conditions. The HT29 background endogenously expresses wild-type HPRT1 and maintains functional purine metabolism, making it an ideal host for investigating the metabolic rewiring that accompanies HPRT1 loss in a colorectal cancer context.
HPRT1 encodes a purine salvage enzyme that catalyzes the conversion of hypoxanthine and guanine, in the presence of phosphoribosyl pyrophosphate (PRPP), into the corresponding nucleotides inosine monophosphate (IMP) and guanosine monophosphate (GMP). The active enzyme forms a homotetramer and is transcriptionally regulated by upstream factors including SP1 and AP-2 transcription factors. Operationally, HPRT1 functions within the broader purine salvage pathway alongside adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP), and adenine phosphoribosyltransferase (APRT), and lies upstream of IMP dehydrogenase (IMPDH) and GMP synthase (GMPS), which channel IMP and GMP into the de novo nucleotide biosynthesis network, ultimately supporting DNA and RNA synthesis.
CRISPR/Cas9-mediated disruption of HPRT1 in HT29 cells abrogates the purine salvage pathway, enforcing cellular reliance on the de novo synthesis of purine nucleotides. This metabolic reprogramming not only provides a powerful model for investigating purine metabolism in colorectal adenocarcinoma but also confers resistance to purine analogs such as 6-thioguanine, enabling its use as a selectable marker. The knockout model is consequently instrumental for exploring metabolic vulnerabilities in cancer, hyperuricemia, gout, and the neurologic disorder Lesch-Nyhan syndrome, which results from inherited HPRT1 deficiency. Its epithelial colon cancer origin further extends its relevance to pathophysiological studies of intestinal purine handling and tumor metabolism.
Researchers can employ this polyclonal knockout population in a wide array of functional assays, including Western blot verification of HPRT1 protein loss, RT-qPCR quantification of residual HPRT1 mRNA, and 6-thioguanine resistance growth assays to functionally confirm purine salvage deficiency. Additionally, HAT medium sensitivity testing provides a classic counterselection method for HPRT1 activity, while intracellular nucleotide pool analysis via HPLC illuminates shifts in IMP and GMP levels. The model also supports cancer metabolism research, drug resistance screening, and genetic selection strategies. For further technical insights or to discuss custom applications, please contact Ascent Research.
