Robust up-regulation of nuclear red fluorescent-tagged fos marks neuronal activation in green fluorescent vasopressin neurons after osmotic stimulation in a double-transgenic rat.
The up-regulation in the expression of mRNA or protein encoded by the c-fos gene is widely used as a marker of neuronal activation elicited by various stimuli. To facilitate the detection of activated neurons, we generated transgenic rats expressing a fusion gene consisting of c-fos coding sequences in frame with monomeric red fluorescent protein 1 (mRFP1) under the control of c-fos gene regulatory sequences (c-fos-mRFP1 rats). In c-fos-mRFP1 transgenic rats, 90 min after hypertonic saline ip administration, nuclear mRFP1 fluorescence was observed abundantly in brain regions known to be osmosensitive, namely the median preoptic nucleus, organum vasculosum lamina terminalis, supraoptic nucleus, paraventricular nucleus, and subfornical organ. Immunohistochemistry for Fos protein confirmed that the distribution of Fos-like immunoreactivity in nontransgenic rats was similar to those of mRFP1 fluorescence after ip administration of hypertonic saline in the transgenic rats. Several double-transgenic rats were obtained from matings between transgenic rats expressing an arginine vasopressin-enhanced green fluorescent protein fusion gene (AVP-eGFP rats) and c-fos-mRFP1 rats. In these double-transgenic rats, almost all eGFP neurons in the supraoptic nucleus and PVN expressed nuclear mRFP1 fluorescence 90 min after hypertonic saline administration. The c-fos-mRFP1 rats are a powerful tool that enables the facile identification of activated neurons in the nervous system. Furthermore, when combined with transgenes expressing another fluorophore under the control of cell-specific regulatory sequences, activation of specific neuronal cell types in response to physiological cues can be readily detected.
Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan.
Hiroaki
H
Fujihara
Yoichi
Y
Ueta
Hitoshi
H
Suzuki
Akiko
A
Katoh
Toyoaki
T
Ohbuchi
Hiroki
H
Otsubo
Govindan
G
Dayanithi
David
D
Murphy
D000818:Animals; D001127:Arginine Vasopressin / Q000235:genetics / Q000378:metabolism*; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D005260:Female; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D007031:Hypothalamus / Q000166:cytology / Q000378:metabolism; D007150:Immunohistochemistry; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D009474:Neurons / Q000378:metabolism*; D010286:Paraventricular Hypothalamic Nucleus / Q000166:cytology / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D055647:Rats, Transgenic; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D012462:Saline Solution, Hypertonic / Q000008:administration & dosage / Q000494:pharmacology; D013356:Subfornical Organ / Q000166:cytology / Q000378:metabolism; D013495:Supraoptic Nucleus / Q000166:cytology / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects; D000097573:Red Fluorescent Protein
D001127:Arginine Vasopressin; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D016760:Proto-Oncogene Proteins c-fos; D011993:Recombinant Fusion Proteins; D012462:Saline Solution, Hypertonic; D000097573:Red Fluorescent Protein