LOCALIZATION OF THE MESSENGER-RNA FOR THE C-JUN NH2-TERMINAL KINASE KINASE IN THE ADULT AND DEVELOPING RAT-BRAIN - AN IN-SITU HYBRIDIZATIONSTUDY

Stress-activated protein kinase/extracellular signal-regulated protein kinase-1/c-Jun NH2-terminal kinase kinase is a dual-specificity kinas e which phosphorylates and activates stress-activated protein kinase/c -Jun NH2-terminal kinase, a recently discovered mitogen-activated prot ein kinase that is stimulated by stressful stimuli and that regulates cellular transcriptional activity. The distribution of the messenger R NA encoding for stress-activated protein kinase/extracellular signal-r egulated protein kinase-1 was evaluated in the adult and developing ra t central nervous system. In situ hybridization with a S-35-labelled 4 5mer oligodeoxynucleotide probe was used to map the distribution of th e stress-activated protein kinase/extracellular signal-regulated prote in kinase-1 messenger RNA in postnatal day 1, 3, 6, 9, 12, 15, 18, 21 and adult rat brains. Specific labelling was generally associated with neuronal profiles. In the adult central nervous system, high hybridiz ation signals were observed in;he hippocampus, the granular layer of t he cerebellum, the medial habenula, the anterodorsal thalamic nucleus, the red nucleus, the pontine nuclei, the facial nucleus, the motor an d mesencephalic nuclei of the trigeminal nerve, the hypoglossal nucleu s, the vestibular nucleus and the nucleus ambiguus. Intermediate level s were present in diencephalic and mesencephalic regions and in tile n eocortex, while basal ganglia displayed a low hybridization signal. In the developing brain, the heterogeneous distribution of the hybridiza tion signal observed in the adult brain was already present, but in th e hippocampus and basal ganglia the stress-activated protein kinase/ex tracellular signal-regulated protein kinase-1 messenger RNA levels wer e significantly higher at postnatal day 3 and during the second postna tal week than in the adult. The results show that stress-activated pro tein kinase/extracellular signal-regulated protein kinase-1 is widely expressed in the rat central nervous system and co-localizes with its substrate stress-activated protein kinase. The observed changes in str ess-activated protein kinase/extracellular signal-regulated protein ki nase-1 messenger RNA levels during postnatal development suggest a rol e for this protein in the maturation of brain circuits. (C) 1997 IBRO. Published by Elsevier Science Ltd.