Embryonic Lethal Phenotyping to Identify Candidate Genes Related with Birth Defects

Area of Science:

• Developmental Biology
• Genetics
• Human Disease Pathology

Background:

• Congenital birth defects are a major cause of infant mortality and disability.
• Understanding the genetic mechanisms of these defects is crucial for clinical intervention.

Purpose of the Study:

• To analyze embryonic and perinatal phenotypes of lethal mutant strains generated by random mutagenesis.
• To identify genes and pathways involved in congenital defects.
• To explore potential links between mutations and human diseases and obesity.

Main Methods:

• Generated and phenotyped 55 lethal mutant strains carrying piggyBac (PB) transposon inserts.
• Utilized Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses.
• Examined gross morphology, developmental delays, and specific organ system defects (brain, heart, vasculature).

Main Results:

• 53 strains were confirmed as embryonic or perinatal lethal.
• Common phenotypes included abnormal body size, developmental delay, brain defects, and cardiovascular abnormalities.
• Twelve mutated loci are known to be associated with human diseases.
• Heterozygotes of eight strains, including the TGF-β signaling gene Smad2, showed altered body weight and composition.

Conclusions:

• Mutations in genes crucial for heart and nervous system development, and Notch/Wnt signaling, contribute to congenital defects.
• This study provides a valuable resource for understanding mammalian embryonic development and congenital birth defect pathology.
• Identified a link between Smad2 heterozygosity and altered energy metabolism, suggesting implications for obesity etiology.