International Mammalian Genome Society

The 15th International Mouse Genome Conference (2001)

Table of Contents * Complex Genetics * Developmental Genetics * Gene Annotation * Gene Discovery * Genome Sequencing * Functional Genomics * Mutagenesis * Presentations * Verne Chapman Memorial Lecture

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POSTER 65 - THE X-LINKED MOUSE MUTATION BENT TAIL IS ASSOCIATED WITH A DELETION OF THE ZIC3 LOCUS

Ms Tessa Carrel
Children's Research Institute & Dept of Pediatrics
The Ohio State University
Columbus OH 43221
USA

Co-Authors: 1) Purandare SM, 2) Parker M, 2) Fox T, 1) Casey B, 2) Herman GE
Institutions: 1) Dept of Pathology, Baylor College of Medicine, 2) Children’s Research Institute & Dept of Pediatrics, The Ohio State University

Bent tail (Bn) is a spontaneous X-linked mutation that produces tail deformities and, occasionally, an open neural tube.  We have demonstrated that the Bn mutation is associated with a 60-170 kb submicroscopic deletion that includes the entire Zic3 locus.  Human mutations in ZIC3 are associated with left-right axis malformations and anal defects, including NTDs. Situs anomalies were found in Bn males and females, the most frequent being partial abdominal situs ambiguus.   The laboratory of Dr. Brett Casey has constructed a mouse strain carrying a targeted null allele of Zic3, which has a strikingly similar phenotype to mice with the Bn mutation.  By analyzing 153 progeny from complementation breeding between Bn females and Zic3 deficient males, we believe that the Bn phenotype is due solely to the absence of the Zic3 gene.  Clinical studies in humans have shown that, during pregnancy, maternal diets enriched in folic acid can reduce the occurrence of most NTDs, even if the offspring are genetically predisposed.  Feeding Bn females folic acid enriched or depleted diets had no effect on the frequency or the severity of the Bn phenotype in the viable progeny.  We are currently investigating the effect on developing Bn embryos.  Finally, by breeding both Bn and Zic3-/- alleles onto different genetic backgrounds, we have been able to separate the tail and situs phenotypes.  This will allow us to map modifier loci for each phenotype individually.