Zap70^mrtle

This phenotypic mutation, identified in an ENU mutagenesis screen, is a T-to-C transition at nucleotide position 1601 that results in replacement of tryptophan by arginine at amino acid position 504 of the protein (W504R), which resides in the kinase domain. The level of the protein in homozygous and heterozygous mutant thymocytes is approximately 25% and 50% that in wild-type thymocytes, respectively.