DIFFERENTIALLY EXPRESSED OLFACTOMEDIN-RELATED GLYCOPROTEINS (PANCORTINS) IN THE BRAIN

Messenger RNA differential display is conducted to search for genes th at are expressed in a region-specific pattern in the rodent brain. Ele ven novel gene fragments are isolated. One of these genes which we cal l pancortin, based on its predominant mRNA expression in the cerebral cortex of the adult, is studied. These pancortin cDNA clones are group ed into four different types of cDNA, designated as pancortin-1 to -4. All pancortin cDNAs share a common sequence in the middle of their st ructure, having two alternative sequences at both 5'- and 3'-ends, res pectively. Deduced amino acid sequence shows that all pancortins have sequences of hydrophobic amino acids at N-terminus and no obvious memb rane spanning regions. In situ hybridization histochemistry using olig onucleotide probes specific for 5'- and 3'-end variable parts has reve aled that these four pancortin mRNAs are expressed differentially in t he adult rodent brain. Robust expression of pancortin-1 and -2 mRNA is observed in the cerebral cortex (including the hippocampus and the ol factory bulb). However, Little of pancortin-3 and -4 mRNA is observed there. In the cortex, some neurons are stained by an antibody raised a gainst Pancortin. Immuno-electron microscopic study has revealed that Pancortin-like immunoreactive products are localized mainly in the end oplasmic reticulum and not in the Golgi apparatus indicating that Panc ortins are the endoplasmic reticulum-anchored proteins. Our results su ggest that each Pancortin is differentially regulated and may perform different functions in the brain. (C) 1998 Elsevier Science B.V.