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Functional Characterization of the Murine Serotonin Transporter Gene Promoter in Serotonergic Raphe Neurons
Author(s) -
Heils Armin,
Wichems Christine,
Mössner Rainald,
Petri Susanne,
Glatz Katharina,
Bengel Dietmar,
Murphy Dennis L.,
Lesch KlausPeter
Publication year - 1998
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1998.70030932.x
Subject(s) - serotonergic , biology , microbiology and biotechnology , caat box , promoter , reporter gene , tata box , serotonin transporter , transcription factor , gene expression , gene , serotonin , genetics , receptor
We have isolated and characterized the 5′‐flanking regulatory region of the murine serotonin 5‐HT transporter (5‐HTT) gene. A TATA‐like motif and several potential binding sites for transcription factors, including two AP1, several AP2 and AP4 binding sites, CCAAT and GC boxes (SP1 binding sites), a nuclear factor‐κB, and a cyclic AMP response element‐like motif, are present in the 5′‐flanking region. A ∼2.2‐kb fragment (−2,143 to +51 with respect to the transcription start site), which had been fused to the luciferase reporter gene and transiently expressed in a 5‐HTT‐expressing cell line and in serotonergic raphe neurons derived from embryonic rat brain‐stem, displayed both constitutive and inducible promoter activity. Functional promoter mapping revealed two clusters of activating elements from bp −82 to −527 and bp −1,001 to −1,937. A cell/neuron‐selective silencer element(s) is contained between bp −294 and −527. Our findings suggest that (1) the murine 5‐HTT gene promoter is active in serotonergic raphe neurons but significantly repressed in neuronal cells from frontal cortex that do not express 5‐HTT, (2) the information contained within ∼0.5 kb of the 5′‐flanking sequence is sufficient to confer its cell‐selective expression, (3) the promoter responds to cyclic AMP‐ and protein kinase C‐dependent induction, and (4) the expression of the 5‐HTT is regulated by a combination of positive and negative cis ‐acting elements operating through a basal promoter unit defined by a TATA‐like motif. Fusion of the 5‐HTT gene promoter unit to a gene of choice may aid its cell‐selective expression in transgenic strategies.