MOLECULAR-CLONING OF A PARTIAL CDNA OF THE INTERLEUKIN-2 RECEPTOR-BETA IN NORMAL MOUSE-BRAIN - IN-SITU LOCALIZATION IN THE HIPPOCAMPUS AND EXPRESSION BY NEUROBLASTOMA-CELLS

While interleukin-2 (IL-2) has been shown to produce a variety of effects in the CNS and has recently been implicated as an endogenous brain neurokine, little is known about the molecular biology of IL-2 receptors in normal brain. The present investigation provides the first evidence that mRNA for IL-2 receptor-beta (IL-2R beta), an essential subunit for signal transduction by peripheral immune cells, is expressed in normal murine forebrain. Using polymerase chain reaction (PCR) cloning, a partial cDNA (349 bp) corresponding to the extracellular domain was cloned and found to have the identical sequence as the lymphocyte IL-2R beta. IL-2R beta mRNA expression was confirmed by a ribonuclease protection assay, and using in situ hybridization histochemistry, IL-2R beta mRNA was localized in the hippocampus where an intense signal was present over the neuron-rich granule cells of the dentate gyrus and Ammon's horn. Moreover, cDNA clones obtained from two murine neuroblastoma cell lines exhibited the same sequence as IL-2R beta cDNA from normal brain. IL-2R beta gene expression was also detected in the frontal cortex and striatum using PCR. Further in situ hybridization studies will be important to extend this intial observation to determine the brain regional localization and cell-specific anatomy of IL-2R beta mRNA in the CNS.