International Mammalian Genome Society

F24 Fine Mapping and FISH Analysis of a Mouse T(2;13) Translocation Causing Neurological, Coat Color and Developmental Abnormalities

Mary Guarnieri^1,2, Nestor Cacheiro³ and Lorraine Flaherty^1,2. ¹Molecular Genetics Program, Wadsworth Center, Albany, NY; ²School of Public Health, SUNY Albany; ³Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee

A chlorambucil-induced chromosomal translocation T(2;13) causes a series of abnormalities throughout mouse development. The presence of one copy of this translocation causes abnormal eyelid formation as well as a series of neurological and physiological abnormalities. This mutant has been called Doe, standing for Dominant open-eyelids. Doe/+ mice exhibit star-gazing activity, hyperactivity, occasional circling and a dilute coat color. They die young of unknown causes. At 3-6 months, Doe/+ mice show signs of glomerulonephritis and periarteritis around major heart vessels, conditions which may be contributing to their early death.

Previous studies have mapped the genes determining this mutant phenotype to both chromosomes 2 and 13, and cytogenetic analysis confirmed that it maps to the translocation breakpoint. This breakpoint resides at the proximal end of chromosome 2 at band A2, and on chromosome 13 at band A4. Further genetic studies have mapped the breakpoint on chromosome 13 between SSLP markers D13Mit16 and D13Mit64.

Using fluorescent in-situ hybridization (FISH), we have mapped the position of this mutation/translocation more precisely. BACs from chromosome 13 were FITC labeled and hybridized to chromosomal spreads bearing the T(2;13) translocation. Hybridization patterns showed that the translocation breakpoint lies between the SSLP markers D13Mit88 and D13Mit119. Thus, we have pinpointed this mutation/translocation to a 2cM critical region. Additional FISH experiments with BACs isolated from this region are under way.