Vk167/PEPS is a transgene with a truncated region upstream of the promoter. The Igk (immunoglobulin kappa) sequence was further modified in the current strain through the insertion of 5 tandem repeats of a 20-bp adenine/thymine (A/T) fragment near the 3' end of the variable region. This "TgA" line has an A/T sequence comparable to that found in line "TgG" without the single cytosine:guanine (C:G) insert. (J:139793)