Rescue of the neural tube defect of loop-tail mice by a BAC clone containing the Ltap gene

Genomics. 2003 Sep;82(3):397-400. doi: 10.1016/s0888-7543(03)00113-7.


The mouse mutant loop-tail (Lp) is an accepted model for the study of neural tube defects (NTDs) in humans. Whereas Lp/+ heterozygotes show a mild tail defect (looped), homozygous Lp/Lp embryos show a very severe form of NTD, with a completely open neural tube from the hindbrain region to the caudal portion of the spinal cord (craniorachischisis). We have recently identified a positional candidate for Lp on chromosome 1, designated as Ltap. Here, we have used an in vivo complementation approach in transgenic mice to attempt to correct the looped-tail phenotype with a bacterial artificial chromosome clone (BAC280A23) that harbors a full-length copy of the Ltap gene. Genotype:phenotype correlations in Lp/+ heterozygotes carrying BAC280A23 show that this clone can rescue the looped-tail phenotype in two independent founder lines (P < 0.05 and P < 0.0001). Importantly, BAC280A23 is also observed to rescue the lethal NTD of Lp/Lp homozygotes, because several viable transgenic Lp/Lp mice could be identified and appeared normal (P < 0.05). Results from these gain-of-function transgenic animals strongly suggest that the positional candidate Ltap present in this BAC is indeed the gene that is defective in loop-tail.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chromosomes, Artificial, Bacterial
  • Mice
  • Mice, Transgenic
  • Nerve Tissue Proteins / genetics*
  • Nerve Tissue Proteins / metabolism
  • Neural Tube Defects / genetics*
  • Neural Tube Defects / metabolism


  • Ltap protein, mouse
  • Nerve Tissue Proteins