Rat LCR1: cloning and cellular distribution of a putative chemokine receptor in brain.

We report here the isolation and localization of RLCR1, a rat G-protein-coupled receptor, which is the homologue (94% amino acid identity) of the bovine receptor (LCR1) isolated from a locus coeruleus cDNA library. The deduced amino acid sequence of the RLCR1 encodes a protein of 347 amino acids and yields a hydropathicity profile characteristic of receptors with seven putative transmembrane regions. The structure of the receptor protein encoded by RLCR1 is most similar to that of the Burkitt's lymphoma receptor 2 (43% identical) and C-C chemokine receptor type 1 (38%). The mRNA corresponding to the cDNA was detected in various rat tissues including spleen, liver, heart, and brain. In situ hybridization analysis shows that RLCR1 is distributed both in neurons and glia in the adult rat brain. Levels of RLCR1 mRNA are highest in the ependymal layer as previously reported. In addition, we found that RLCR1 is also expressed at lower levels in cerebral cortex, hippocampus, cerebellum, and brainstem. The finding that LCR1 is expressed in the adult indicates that this receptor influences neuronal function at times after maturation of the brain.