Further characterization of the genetic defect of the Bent tail mouse, a mouse model for human neural tube defects.

Further characterization of the genetic defect of the Bent tail mouse, a mouse model for human neural tube defects.

Klootwijk R, Schijvenaars MM, Mariman EC, Franke B.

Department of Human Genetics, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands.

BACKGROUND: Neural tube defects (NTDs) are congenital malformations arising mostly from incomplete neural tube closure during early embryogenesis. Most NTDs in humans have a complex etiology, with involvement of both genetic and environmental factors. More than 100 mouse models for human neural tube defects exist; Bent tail is one of them. The mouse mutant is caused by a submicroscopic deletion on Xq that completely encompasses the Zic3 gene. METHODS: We searched the ENSEMBL database for other genes/transcribed sequences in the Bent tail deletion in addition to Zic3, which we confirmed by PCR analysis. RESULTS: In our study, we show that the Bent tail deletion is at least 300 kb in size, encompassing a processed pseudogene and a number of expressed sequence tags in addition to Zic3. Although more research is needed to clarify the identity and function of the deleted transcripts, most of them are expressed during embryonic development and might therefore contribute to the phenotype of the Bent tail mouse. CONCLUSIONS: This study presents the first evidence for the fact that the Bent tail allele is not merely a Zic3 knockout allele, as has been previously suggested.