TISSUE-SPECIFICITY OF SPONTANEOUS POINT MUTATIONS IN LAMBDA-SUPF TRANSGENIC MICE

Transgenic mice carrying multiple copies of a recoverable lambda phage shuttle vector carrying the supF mutation reporter gene (lambda supF) were constructed for the purpose of studying mutagenesis in a whole a nimal. Spontaneous mutations in rescued supF target genes from mouse l iver and skin were analyzed. The mutation frequency was similar in bot h tissues (in the range of 2 x 10(-5)), but the spectrum of point muta tions was distinct, with transitions common in the skin and transversi ons more prominent in the liver (P = 0.01). These results may help to elucidate pathways of endogenous mutagenesis in vivo, and they illustr ate potentially important tissue-specific differences in genetic insta bility. (C) 1996 Wiley-Liss, Inc.