RAG Cells

The RAG cell line is a nonreverting 8-azaguanine-resistant mutant derived from a renal adenocarcinoma of BALB/c mice. This line was developed through alternate animal-to-tissue culture passages to enrich for the tumorigenic population while eliminating normal stromal fibroblasts. RAG cells display an ameboid to epithelioid morphology with prominent cytoplasmic processes and are resistant to hypoxanthine-guanine phosphoribosyltransferase (HGPRT)-dependent selection methods due to their enzymatic deficiency. This resistance has facilitated their use in biochemical selection systems for somatic cell hybridization experiments.

RAG cells are widely utilized as a parental line in somatic cell fusion studies due to their compatibility with fusion procedures using inactivated Sendai virus. When fused with other cell lines, such as LM(TK-) or WI-38, the hybrids retain marker chromosomes and exhibit biochemical complementation of metabolic deficiencies. These hybrids have been instrumental in mapping genetic regulatory elements and studying gene expression, particularly in kidney-associated enzymes like the ES-2 esterase. RAG hybrids provide insights into both inter- and intraspecific chromosomal segregation and functional genomics.

In addition to their role in hybridization studies, RAG cells have served as a model to study the epigenetic regulation of gene expression. Hybrid cells involving RAG often show extinction and re-expression of specific genetic traits, depending on the retention or loss of particular chromosomes. This makes the RAG cell line a valuable tool in understanding the dynamics of genetic regulation and chromosomal stability in tumorigenic cells.