Heterozyogus Trp53 truncation mutation | Mice heterozyogous for an allele of p53 that removes the 5' portion of the protein demonstrate decreased cancer, permature aging phenotypes, and shortened lifespan in the mixed inbred C57BL/6â129/Sv background. It has been proposed that the this allele of p53 results in increased activity/overexpression [11780111]. | Mouse | — | — | — |