Novel dual repressor elements for neuronal cell-specific transcription of the rat 5-HT1A receptor gene.
The level of expression of the 5-HT1A receptor in the raphe and limbic systems is implicated in the etiology and treatment of major depression and anxiety disorders. The rat 5-HT1A receptor gene is regulated by a proximal TATA-driven promoter and by upstream repressors that inhibit gene expression. Deletion of a 71-base pair (bp) segment between -1590/-1519 bp of the 5-HT1A receptor gene induced over 10-fold enhancement of transcriptional activity in both 5-HT1A receptor-expressing (RN46A raphe and SN48 septal) cells and receptor-negative (L6 myoblast and C6 glioma) cells. A 31-bp segment of the repressor was protected from DNase I digestion by RN46A or L6 nuclear extracts. Within the 31-bp segment, a single protein complex was present in receptor-expressing cells that bound a novel 14-bp DNA element; in receptor-negative cells, an additional complex bound an adjacent 12-bp sequence. In receptor-positive but not receptor-negative cells, mutation of the 14-bp element to eliminate protein binding abrogated repression to nearly the same extent as deletion of the -1590/-1519 bp segment. Additional mutation of both 14-bp and 12-bp elements abolished protein binding and repressor activity in receptor-negative cells. Thus a single protein-DNA complex at the 14-bp element represses the 5-HT1A receptor gene in 5-HT1A receptor-positive neuronal cells, whereas adjacent DNA elements provide a dual repression mechanism in 5-HT1A receptor-negative cells.
Ou
X M
XM
Neuroscience Research Institute, University of Ottawa, 451 Smyth Road, Ottawa K1H 8M5, Canada.
Jafar-Nejad
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H
Storring
J M
JM
Meng
J H
JH
Lemonde
S
S
Albert
P R
PR
D000818:Animals; D001008:Anxiety Disorders / Q000209:etiology; D004268:DNA-Binding Proteins / Q000378:metabolism; D003866:Depressive Disorder / Q000209:etiology; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D009474:Neurons / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011903:Raphe Nuclei / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D011985:Receptors, Serotonin / Q000096:biosynthesis / Q000235:genetics*; D044263:Receptors, Serotonin, 5-HT1; D012045:Regulatory Sequences, Nucleic Acid; D020665:Septum of Brain / Q000166:cytology / Q000378:metabolism; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1