Induction of members of the Fos/Jun family of immediate-early genes in identified hypothalamic neurons: in vivo evidence for differential regulation.
In situ hybridization was used to measure the expression of members of the Fos/Jun family of immediate-early genes in hypothalamic neurons in vivo following defined stimuli that utilize different afferent pathways. Only c-jun messenger RNA was expressed in the hypothalamic supraoptic and paraventricular nuclei of control animals. Intravenous infusions of sodium chloride solutions of different tonicity produced a range of plasma osmolalities within physiological limits. While the induction of c-fos and jun B messenger RNAs followed the stimulus intensity, the expression of c-jun was repressed at low levels of stimulation. A higher level of osmotic stimulation was able to co-induce c-jun with the c-fos, jun B and fos B genes, suggesting that other signalling pathways may then be activated. Parturition or systemic administration of cholecystokinin, that activate supraoptic and paraventricular neurons via ascending afferent pathways from the brainstem, both induced c-fos, but not the other genes, in the magnocellular nuclei. Use of double in situ hybridization confirmed that, unlike with osmotic stimulation, induction of c-fos only occurred in oxytocin neurons. These two stimuli did not cause a concomitant repression of c-jun messenger RNA expression in magnocellular oxytocin neurons. These patterns of induction provide evidence for the differential regulation of members of this family of genes in a physiological context.
Luckman
S M
SM
Department of Neurobiology, Babraham Institute, Cambridge, U.K.
Dye
S
S
Cox
H J
HJ
D000818:Animals; D016375:Antisense Elements (Genetics); D002766:Cholecystokinin / Q000494:pharmacology; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D017781:Genes, Immediate-Early; D016762:Genes, fos; D016758:Genes, jun; D007031:Hypothalamus / Q000378:metabolism*; D017403:In Situ Hybridization; D007262:Infusions, Intravenous; D008297:Male; D005810:Multigene Family; D009474:Neurons / Q000378:metabolism*; D009928:Organ Specificity; D009994:Osmolar Concentration; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis; D016755:Proto-Oncogene Proteins c-jun / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D012965:Sodium Chloride / Q000008:administration & dosage / Q000494:pharmacology; D013495:Supraoptic Nucleus / Q000378:metabolism; D014158:Transcription, Genetic
D016375:Antisense Elements (Genetics); D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D012965:Sodium Chloride; D002766:Cholecystokinin