The mouse promoter drives B cell-specific expression of the human MYC coding sequence (exons 2 and 3; Genbank vector OQ428542). A codon mutation generates a STOP codon at the third codon (TCG to TAG) and prevents expression of MYC. The codon substitution created a DGYW motif, a known preferential target sequence for somatic hypermutation, that can activate MYC translation following sporadic reversion. This vector lacks the loxP site found in Tg(Igkv3-5*-MYC)24Plbe. In line 5 the transgene inserted at chr1:180288300-180308245. (J:131912)