A transgenic construct containing cDNA encoding the mutant human ubiquitin B, UBB+1 sequence (in the +1 reading frame), under the direction of the mouse Thy1.2 promoter was injected into fertilized FVB/N mouse eggs. Founder line 8630 with 2 copies of the transgene was subsequently established. mRNA levels for UBB+1 are 67% of endogenous Ubb mRNA levels. (J:147938)