Ribonucleotide reductase subunit R1: a gene conferring sensitivity to valproic acid-induced neural tube defects in...

Area of Science:

• Developmental biology
• Neuroscience
• Genetics

Background:

• Neural tube defects (NTDs) are common but etiologically complex, with closure occurring at four distinct mammalian sites.
• Understanding region-specific genetic mechanisms in NTDs is crucial for mechanistic interpretation and targeted interventions.

Purpose of the Study:

• To identify neural tube closure site-specific genes involved in teratogen-induced NTDs.
• To investigate the role of identified genes in the susceptibility to VPA-induced NTDs at closure site II (fore/midbrain).

Main Methods:

• Utilized a VPA-sensitive mouse model (SWV/Fnn) with high susceptibility to NTDs at closure site II.
• Employed cDNA library sequencing to identify VPA-sensitive, closure site II-specific genes.
• Quantified rnr-r1 mRNA levels and assessed cellular proliferation using ELISA assays with BrdU labeling in vivo.

Main Results:

• Identified and sequenced a clone encoding the r1 subunit of ribonucleotide reductase (RNR) as a closure site II-specific gene.
• Observed a significant increase in rnr-r1 mRNA abundance following VPA treatment.
• Demonstrated a significant decrease in cellular proliferation in the closure site II neural tube region of VPA-exposed embryos.

Conclusions:

• The r1 subunit of ribonucleotide reductase (RNR) is upregulated by VPA, leading to decreased cell proliferation at neural tube closure site II.
• Hypothesize that rnr-r1 plays a critical role in the pathogenesis of VPA-induced exencephaly.