Whole genome sequencing of mouse lymphoma L5178Y-3.7.2C (TK +/- ) reveals millions of mutations and genetic markers.

The mouse lymphoma L5178Y-3.7.2C (TK+/- ) cell line is extensively used in genetic toxicology to conduct the mouse lymphoma assay (MLA). The MLA is used to establish the mutagenic and clastogenic effects of chemicals and pharmaceuticals, and is one of the few genetic tests widely accepted by regulatory agencies throughout the world. Despite the extensive use and regulatory impact of L5178Y-3.7.2C (TK+/- ) cells, little is known about their genetic composition or how it affects the outcome of the MLA. To determine the genetic background of this cell line, we sequenced and analyzed its entire genome. Our results confirm the existence of previously described mutations in the Tk1 and Trp53 genes and catalog millions of other mutations, many of which impair the function of genes with key roles in cell physiology and genetic toxicology.