Spatiotemporal patterns of the Huntingtin-interacting protein 1-related gene in the mouse head.

Huntingtin-interacting protein 1-related (Hip1r) was originally identified due to its homology to Huntingtin-interacting protein 1, which contributes to the development of Huntington's disease (HD). We studied the expression of the mouse Hip1r (mHip1r) gene in the mouse head by in situ hybridization. In early embryogenesis at embryonic day (E) 13, mHip1r expression was especially prominent in the olfactory epithelium, cerebral cortex layer 1, cortical plate, and dentate gyrus. During later development from E15 to E17, strong expression of mHip1r transcripts continued to be observed in the olfactory epithelium, cortical plate, and dentate gyrus. Furthermore, not only the subplate and subventricular zone of the cortex, but also secretory glands, such as the nasal gland and the submandibular gland, were mHip1r-positive. Other positive tissues included the retinal ganglion cells, vomeronasal organ, trigeminal ganglion, and the developing molar tooth. In the adult mouse brain, similar expression patterns were observed in the cerebral cortex layers and other brain regions except the cerebellum. Additionally, by using an antibody against mHip1r, we confirmed these expression patterns at the protein level. Specific expression of mHip1r in the embryonic brain and secretory glands suggests a possible role for Hip1r in normal development and in the pathology of HD.