DHFR and folate deficiency: The topological chromatin domains from human and mouse cells showed very similar TAD structures in syntenic regions, indicating that mice could serve as a suitable model system for studying 3D genome alterations in NTDs.[15] To investigate how folate deficiency comprehensively regulates the 3D genome structure in NTD, we established an NTD mouse model using methotrexate (MTX) as previously reported.[16] MTX is a potent analog belonging to a class of specific inhibitors of dihydrofolate reductase (DHFR) that prevents the conversion of folate to its active form.