Neural tube defects without neural crest defects in splotch mice

Area of Science:

• Developmental biology
• Genetics
• Teratology

Background:

• Homozygous Splotch mutant mice (Sp/Sp) display embryonic lethality by day 14 of gestation.
• Key phenotypes include neural tube defects, curly tail, and malformations of neural crest derivatives.
• The Sp1H allele, a radiation-induced mutation, presents a similar phenotype and was utilized in this study.

Purpose of the Study:

• To investigate rare occurrences of neural tube and tail defects in offspring from Splotch (Sp1H) heterozygote crosses.
• To explore the relationship between neural tube defects and neural crest defects in the Splotch mutant model.
• To determine if these defects arise from independent mechanisms or gene dosage effects.

Main Methods:

• Utilized Sp1H mutant mice, a specific allele of the Splotch mutation.
• Analyzed offspring from crosses between Splotch (Sp1H) heterozygotes.
• Phenotypic characterization focused on neural tube, tail, and neural crest development.

Main Results:

• Observed rare cases of neural tube and tail defects in the offspring.
• Notably, these defects were not consistently associated with neural crest abnormalities.
• Neural tube defects were primarily localized to the lumbosacral region, with occasional hindbrain involvement.

Conclusions:

• The findings suggest that neural tube and neural crest defects in Splotch mutants may develop through independent pathways.
• Alternatively, the severity and presence of these defects could be influenced by the dosage of the mutant gene.
• Different genetic thresholds may exist for the pathogenesis of neural tube versus neural crest defects in this model.