DISTRIBUTION OF MESSENGER-RNA ENCODING TAT-BINDING PROTEIN-1 (TBP-1),A COMPONENT OF 26S PROTEASOME, IN THE RAT-BRAIN

Cellular localization of Tat-binding protein-1 (TBP-1) mRNA is studied in the rat central nervous system (CNS) by in situ hybridization hist ochemistry. TBP-1 is one of the molecules which interact with HIV Tat and influence HIV amplification. Also, TBP-1 is recognized as a compon ent of a 19S regulatory subunit of the 26S proteasome which degrades u biquitinated proteins and is essential for a remarkably wide range of cellular processes, including vesicle fusion, proteolysis, peroxisomal and mitochondrial biogenesis and transcription. A detectable amount o f TBP-1 mRNA exists widely in neurons but with high heterogeneity in t he CNS. Many motor neurons, e.g. those in the oculomotor nucleus, troc hlear nucleus, motor trigeminal nucleus, facial nucleus and hypoglossa l nucleus, are TBP-1 mRNA positive. In addition, neurons in the sensor y nuclei, such as the mesencephalic trigeminal nucleus and the nucleus ambiguus, and many cortical neurons are TBP-1 mRNA positive. These re sults suggest that TBP-I is one of the basic molecules in the brain an d that the expression of TBP-1 mRNA is differentially regulated at the cellular level, probably reflecting the rate of protein turnover as a whole. (C) 1998 Elsevier Science B.V.