Localization of mRNAs for Rlim-1, the rat Xlim-1 homolog, in the developing rat brain.

We studied the localization of Rlim-1 mRNAs, the rat Xlim-1 homolog, in the developing rat brain using in situ hybridization histochemistry. On embryonic day 13 (E13), strong signals were observed in the most superficial layer of the telencephalon, the zonalimitans intrathalamica, the ventral thalamus, some nuclei of the hypothalamus, the tectum, the cerebellum, the lower brainstem and the spinal cord. In the above-mentioned regions except the cerebellum, the distribution pattern remained almost the same from embryonic stage to adulthood but the intensity of expression gradually decreased after birth. In the cerebellum, the distribution pattern changed. during development; all the primordium of cerebellum in E13, the external granular and the Purkinje cell layers in postnatal day 7 (P7), and only the Purkinje cell layer in the adult expressed positive signals. These results suggest that Rlim-1 may be involved in region specification.