Metaphase FISHing of transgenic mice recommended: FISH and SKY define BAC-mediated balanced translocation.
The evolving trend to use larger transgenes and their associated increased chance of unexpected genetic events mandates more careful characterization of transgenic mice. In characterizing our five new mouse strains transgenic for the BAC, bEMS4, we have identified the highest copy number reported to date: the stable incorporation of approximately 40 copies of a 194-kb expressed transgene in a single insertion site. We caution, however, that standard molecular techniques failed to identify a balanced translocation in another strain, and an inappropriate site of insertion in a third. Molecular cytogenetic analysis using metaphase FISH was the minimum level of characterization needed to reveal these unexpected genetic events. In addition, we combined FISH and SKY to identify the transgene at the breakpoints of the balanced translocation, t(3;9). This is the first description of a BAC-mediated chromosomal rearrangement and the first application of SKY to identify transgene-induced chromosomal rearrangements.
Abrahams
Brett S
BS
Graduate Program in Neuroscience, Department of Medical Genetics, University of Columbia, Vancouver, British Columbia, Canada.
Chong
Annabelle C O
AC
Nisha
Maimun
M
Milette
Danielle
D
Brewster
David A
DA
Berry
Melissa L
ML
Muratkhodjaev
Farkhad
F
Mai
Sabine
S
Rajcan-Separovic
Evica
E
Simpson
Elizabeth M
EM
D000818:Animals; D015139:Blotting, Southern; D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics; D017931:DNA Primers; D015870:Gene Expression; D018014:Gene Transfer Techniques; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008677:Metaphase / Q000235:genetics*; D051379:Mice; D008822:Mice, Transgenic; D016133:Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014178:Translocation, Genetic / Q000235:genetics*
D017931:DNA Primers