Asymmetric regulation by estrogen at the cholinergic gene locus in differentiated NG108-15 neuronal cells.
OBJECTIVE
Estrogen acts as a neurogenerative and neuroprotective factor in the cholinergic system. Choline acetyltransferase (ChAT) and vesicular acetylcholine transporter (VAChT) are regarded as markers of cholinergic neurons. The genes coding these proteins are located at a common locus, the cholinergic gene locus. However, few details concerning activation of the locus have been obtained. We examined the effect of estrogen on the activation pattern of the locus using a cholinergic cell line.


METHODS
NG108-15 neuronal cells, as a model of cholinergic neurons, were used. Dose-dependent effects of estradiol (E2) on the gene expression of ChAT and VAChT were quantitatively determined by a real-time RT-PCR. The expression of ChAT mRNA variants was qualitatively evaluated by RT-PCR using specific primers.


RESULTS
The expression of ChAT and VAChT mRNA was strongly enhanced with the induction of differentiation. The enhanced expression of ChAT mRNA was further increased dose-dependently by E2 (10(-10) to 10(-7)M), while that of VAChT mRNA did not respond to E2. The up-regulation of ChAT mRNA expression by E2 was abolished by co-treatment with a pure-antagonist of estrogen receptors. A qualitative analysis of ChAT mRNA variants revealed the R types, which share a common sequence with the VAChT gene, and type M ChAT mRNA to mainly be expressed, and that the appearance of these variants was not altered by E2.


CONCLUSIONS
The cholinergic gene locus in differentiated NG108-15 neuronal cells is further activated by E2, but the effect is restricted to the transcription of ChAT gene.
Yamamuro
Yutaka
Y
Department of Animal Science, College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa 252-8510, Japan. yamamuro@brs.nihon-u.ac.jp <yamamuro@brs.nihon-u.ac.jp>
Aizawa
Shu
S
D000818:Animals; D052160:Benzothiazoles; D002795:Choline O-Acetyltransferase / Q000096:biosynthesis / Q000235:genetics*; D002799:Cholinergic Fibers / Q000502:physiology*; D003959:Diamines; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology / Q000502:physiology*; D004965:Estrogen Antagonists / Q000494:pharmacology; D000077267:Fulvestrant; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D005796:Genes / Q000187:drug effects / Q000235:genetics; D006822:Hybrid Cells; D051379:Mice; D009930:Organic Chemicals; D011804:Quinolines; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014212:Tretinoin / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects; D050494:Vesicular Acetylcholine Transport Proteins / Q000096:biosynthesis / Q000235:genetics*
D052160:Benzothiazoles; D003959:Diamines; D004965:Estrogen Antagonists; D009930:Organic Chemicals; D011804:Quinolines; D012333:RNA, Messenger; D050494:Vesicular Acetylcholine Transport Proteins; C098022:SYBR Green I; D000077267:Fulvestrant; D004958:Estradiol; D014212:Tretinoin; D002795:Choline O-Acetyltransferase