CYTOGENETIC MAPPING OF LAMBDA-GT10 LACZ SEQUENCES IN THE TRANSGENIC MOUSE STRAIN-40.6 (MUTA(TM)MOUSE)

The transgenic mouse strain 40.6 (Muta(TM)Mouse) was developed for the detection of gene mutations induced in vivo, Strain 40.6 was construc ted by microinjecting the shuttle vector lambda gt10 lacZ into the mal e pronucleus of a single cell embryo resulting from a CD2 (i.e. BALB/c x DBA/2)F-1 x CD2 F-1 cross, Approximately 40 concatenated copies of the shuttle vector were integrated per haploid genome, The resulting m ice were bred to disomy for the insert for use in mutagenicity studies . Ultimately, it is hoped that transgenic rodent model systems such as this one will play an important regulatory role in hazard identificat ion, Despite the increasing use of this strain in toxicological studie s, relatively little is known about the site of integration of the tar get gene into the mouse genome, In this study, fluorescence in situ hy bridization and DAPI chromosome banding were combined to determine the location of the transgenic element in the mouse genome, The results i ndicate that the lambda sequences containing the lacZ gene are located in the B region of mouse chromosome 3. No other major chromosomal rea rrangements were evident in the genome of this mouse strain.