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Updated: Jul 24, 2026
Neural Tube Closure in Mouse Whole Embryo Culture
Published on: October 21, 2011
Circletail, a new mouse mutant with severe neural tube defects: chromosomal localization and interaction with the
J N Murdoch1, R A Rachel, S Shah
1Neural Development Unit, Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK. J.Murdoch@ich.ucl.ac.uk
Abstract:
Circletail (Crc) is a new mouse mutant that exhibits a severe form of neural tube defect, craniorachischisis, in which almost the entire neural tube fails to close. This phenotype is seen in very few other mutants, the best characterized of which is loop-tail (Ltap(Lp), referred to hereafter as Lp). We tested the possibility of allelism between Lp and Crc by intercrossing Lp/+ and Crc/+mice. A proportion of double heterozygotes (Lp/+,Crc/+) exhibit craniorachischisis, revealing failure of complementation. However, genetic analysis shows that Crc is not linked to the markers that flank the Lp locus and cannot, therefore, be an allele of Lp. A genome-wide scan has localized the Crc gene to a region of 8.8 cM on central chromosome 15. Partial penetrance of the craniorachischisis phenotype in Crc/+,Lp/+double heterozygotes suggests the existence of a third, unlinked genetic locus that influences the interaction between Crc and Lp.
Insights
A new mouse mutant, Circletail (Crc), shows severe neural tube defects. While not allelic to loop-tail (Lp), Crc interacts with Lp, suggesting a third genetic factor influences craniorachischisis.
Area of Science:
- Developmental biology
- Genetics
- Mouse models
Background:
- Neural tube defects (NTDs) are severe congenital abnormalities.
- Craniorachischisis, a complete failure of neural tube closure, is rare.
- The loop-tail (Lp) mouse mutant is a key model for studying NTDs.
Purpose of the Study:
- To investigate the genetic basis of the Circletail (Crc) mutation.
- To determine if Crc is allelic to the loop-tail (Lp) mutation.
- To identify genetic interactions influencing craniorachischisis.
Main Methods:
- Intercrossing of Lp/+ and Crc/+ mice to generate double heterozygotes.
- Genetic analysis to test for allelism and linkage.
- Genome-wide scan to localize the Crc gene.
Main Results:
- Double heterozygotes (Lp/+, Crc/+) exhibited craniorachischisis, indicating a failure of complementation.
- Genetic mapping demonstrated that Crc is not linked to the Lp locus, ruling out allelism.
- The Crc gene was localized to chromosome 15.
- Partial penetrance in double heterozygotes suggests interaction with other genes.
Conclusions:
- Circletail (Crc) is a novel mutation causing severe craniorachischisis.
- Crc is genetically distinct from loop-tail (Lp) but interacts with it.
- A third, unlinked locus likely modulates the craniorachischisis phenotype in Crc/Lp interactions.
