The regulatory region 23 (Rr23 or HS746) is a non-coding enhancer element that controls expression of Msx1 (homeobox, msh-like 1), a gene involved in craniofacial development. qPCR analysis indicates a 1.5 fold down regulation of Msx1 in homozygous HS1431 E11.5 and E13.5 embryos. Analysis of the adult skulls from homozygous mice by micro-computed tomography reveals significant differences in skull morphology compared to wild type. Alterations in HS746 include a shortening of the face, a widening of the posterior neurocranium, a narrowing of the palate and shortening of the cranial base. This strain may be useful for downstream analysis of craniofacial development.

In this knockout of the non-coding enhancer element (Rr23or HS746), mRNA expression of Msx1 in mouse embryos is diminished and adult skulls exhibit significant differences in skull morphology. This strain may be useful for downstream analysis of craniofacial development.

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.