Secretagogin is a Ca2+-binding protein identifying prospective extended amygdala neurons in the developing mammalian telencephalon.
The Ca(2+)-binding proteins (CBPs) calbindin D28k, calretinin and parvalbumin are phenotypic markers of functionally diverse subclasses of neurons in the adult brain. The developmental dynamics of CBP expression are precisely timed: calbindin and calretinin are present in prospective cortical interneurons from mid-gestation, while parvalbumin only becomes expressed during the early postnatal period in rodents. Secretagogin (scgn) is a CBP cloned from pancreatic beta and neuroendocrine cells. We hypothesized that scgn may be expressed by particular neuronal contingents during prenatal development of the mammalian telencephalon. We find that scgn is expressed in neurons transiting in the subpallial differentiation zone by embryonic day (E)11 in mouse. From E12, scgn(+) cells commute towards the extended amygdala and colonize the bed nucleus of stria terminalis, the interstitial nucleus of the posterior limb of the anterior commissure, the dorsal substantia innominata (SI) and the central and medial amygdaloid nuclei. Scgn(+) neurons can acquire a cholinergic phenotype in the SI or differentiate into GABA cells in the central amygdala. We also uncover phylogenetic differences in scgn expression as this CBP defines not only neurons destined to the extended amygdala but also cholinergic projection cells and cortical pyramidal cells in the fetal nonhuman primate and human brains, respectively. Overall, our findings emphasize the developmentally shared origins of neurons populating the extended amygdala, and suggest that secretagogin can be relevant to the generation of functional modalities in specific neuronal circuitries.
Mulder
Jan
J
European Neuroscience Institute at Aberdeen, University of Aberdeen, Aberdeen, UK.
Spence
Lauren
L
Tortoriello
Giuseppe
G
Dinieri
Jennifer A
JA
Uhlén
Mathias
M
Shui
Bo
B
Kotlikoff
Michael I
MI
Yanagawa
Yuchio
Y
Aujard
Fabienne
F
Hökfelt
Tomas
T
Hurd
Yasmin L
YL
Harkany
Tibor
T
D000679:Amygdala / Q000166:cytology* / Q000378:metabolism; D000818:Animals; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D016565:Cheirogaleidae / Q000196:embryology; D004622:Embryo, Mammalian / Q000033:anatomy & histology / Q000502:physiology; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D008322:Mammals / Q000033:anatomy & histology / Q000196:embryology / Q000254:growth & development; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D038081:Organogenesis; D064046:Secretagogins; D013687:Telencephalon / Q000166:cytology / Q000196:embryology / Q000254:growth & development
D002135:Calcium-Binding Proteins; C576556:SCGN protein, human; D064046:Secretagogins