ID4 (inhibitor of DNA binding 4) is a transcriptional regulator containing a helix-loop-helix domain and lacking a DNA binding domain. Unique among the ID proteins, ID4 is involved in the regulation of neural stem cell differentiation and proliferation. The Id4 knockout/knockin allele has a GFP reporter and a PGK-neo cassette replacing exons 1-2 of the gene. Uniform GFP expression is observed in all cortical areas by E12.5. Mice homozygous for this null allele exhibit reduced brain size from E11.5, specifically a 30% reduction occurs in the ventricular surface of the telencephalon affecting dorsomedial progenitor zones. Impairment of G1-S cell cycle transition and premature differentiation in early neural stem cells results in reduced brain size in these mice. Like ID2, loss of ID4 affects adipogenesis. Homozygous mice have 50% less body fat weight and adipocyte size is reduced by half. Following 6 weeks on high fat diet, mice gain significantly less weight than wild-type littermates. This strain may be useful for studying ID4 as a regulator of neurogenesis and adipogenesis.

These Id4 knock-in/knock-out mice exhibit reduced brain size, impaired cell cycle transition in early neural stem cells, reduced body fat, resistance to high fat diet and impaired adipocyte differentiation. This strain may be useful for studying ID4 as a regulator of neurogenesis and adipogenesis.

This strain is hosted by NIH's MMRRC, which partners with JAX for the distribution of this and other strains. For additional information and to purchase, please visit the MMRRC site.