Journal of Neuroscience, Vol 15, 4885-4895, Copyright © 1995 by Society for Neuroscience
Characterization of the human 5-HT2A receptor gene promoter
QS Zhu, K Chen and JC Shih
Department of Molecular Pharmacology and Toxicology, School of Pharmacy, University of Southern California, Los Angeles 90033, USA.
The regulation of 5-HT2A receptor (5-HT2AR) expression has been implicated
in a variety of pathological processes and has been shown to be extremely
complicated and controversial. In order to understand the mechanisms of
regulation of this receptor, it is important to characterize its promoter.
In this report, the 5' end of the human 5- HT2AR gene was cloned and
characterized. Anchored PCR mapped multiple transcription initiation sites
at nucleotides -1157, -1137, -1127, and - 496. Transfection of chimeric
growth hormone plasmids containing various DNA fragments into
5-HT2AR-positive human cell lines (SHSY-5Y, neuroblastoma; HeLa, cervix
carcinoma) showed that the 0.74 kb HaeIII/PvuII fragment, which encompasses
the initiation sites between - 1157 and -1127 and 5' of the downstream
initiation site (at -496), exhibited significant promoter activity. This
promoter activity was not affected by the sequence upstream of the 0.74 kb
fragment. The sequence downstream (the 0.45 kb PvuII/SmaI fragment)
strongly repressed this promoter activity, suggesting the presence of a
silencer. Sequence analysis combined with gel retardation and Dnase 1
footprinting assay identified multiple cis and trans elements for this
fragment, including Sp1, PEA3, cyclic AMP response element (CRE)-like
sequence, and E- boxes. Two novel transcription factors have been detected
by gel retardation and DNase 1 footprinting assay; one of them may be
specific for human. The transcription factors and promoter activities were
low in the negative cell line NCI-H460 (human lung large cell carcinoma).
Interestingly, the 0.39 kb fragment, isolated from the 3' end of the 0.74
kb fragment, exhibited the highest promoter activity. The possibility that
this 0.39 kb fragment may be an alternative promoter is discussed. These
new data are essential for further study of the regulation of 5-HT2AR gene
expression.