This transgene expresses a mouse Tnnt2 gene, with codon 92 mutated to encode a tryptophan instead of the arginine and an 11-amino acid c-myc epitope added to the 5' end of the coding region, under the control of a rat alpha-myosin heavy chain promoter. This line expresses 50% of the total Tnnt2 as the mutant transgenic form.