THE IDENTIFICATION OF A NOVEL CDNA PREFERENTIALLY EXPRESSED IN THE OLFACTORY-LIMBIC SYSTEM OF THE ADULT-RAT

To analyze cell-specific brain gene expression, we have developed a PC R-based subtractive hybridization cloning method utilizing trace start ing material, allowing isolation of novel genes expressed under specif ic conditions. Our previous studies indicated that local substantia ni gra (SN) type 1 astrocytes elaborate an array of trophic molecules whi ch support the survival of SN dopaminergic neurons. Therefore, the cur rent study focused on astrocyte gene expression utilizing a type 1 ast rocyte-enriched cDNA library. We report initial characterization of a novel cDNA. designated AT1-46, that is preferentially expressed in the olfactory-limbic system of the adult rat brain. Although AT1-46 is ex pressed widely in the periphery, it is regulated both developmentally and in a cell-specific fashion in the brain. Structurally, AT1-46 is p redicted to encode a highly alpha-helical molecule with several domain s of potential coiled coil formation, and exhibits a 28% amino acid se quence identity with the intermediate filament-associated protein, tri chohyalin.