The -1438A/G polymorphism in the 5-hydroxytryptamine type 2A receptor gene affects promoter activity.
BACKGROUND
The -1438A/G single nucleotide polymorphism (SNP) lies just upstream of two alternative promoters for the 5-hydroxytryptamine type 2A (5-HT2A) receptor gene (HTR2A) and is in strong linkage disequilibrium with the 102T/C SNP. Both SNPs are associated with numerous psychiatric disorders and related phenotypes. A possible functional affect of the -1438A/G SNP might underlie associations of both linked SNPs with these neuropsychiatric disorders. A prior investigation into affects of this SNP on promoter function, lacking the more downstream promoter, found no significant difference with a reporter gene assay.


METHODS
To investigate possible functional effects of -1438A/G on either promoter, two different reporter gene assays were used in three cell lines.


RESULTS
Promoter activity was consistently detected that, in the presence of the SV40 enhancer, was significantly greater in the presence of the A allele relative to the G allele but only in cell lines that express endogenous HTR2A, suggesting that transcriptional factor(s) and the presence of both promoters might be necessary to elicit this effect.


CONCLUSIONS
These findings show that the -1438A/G SNP has the potential to modulate HTR2A promoter activity and might be the functional variant responsible for the associations of both SNPs with many neuropsychiatric phenotypes.
Parsons
Michael J
MJ
Department of Clinical Neuropharmacology, Institute of Psychiatry, King's College London, London, United Kingdom. spklmjp@iop.kcl.ac.uk
D'Souza
Ursula M
UM
Arranz
Maria-Jesus
MJ
Kerwin
Robert W
RW
Makoff
Andrew J
AJ
D000409:Alanine / Q000235:genetics; D045744:Cell Line, Tumor; D015500:Chloramphenicol O-Acetyltransferase / Q000378:metabolism; D003545:Cysteine / Q000235:genetics; D017930:Genes, Reporter / Q000502:physiology; D005998:Glycine / Q000235:genetics; D006801:Humans; D015810:Linkage Disequilibrium; D009447:Neuroblastoma; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000502:physiology*; D044402:Receptor, Serotonin, 5-HT2A / Q000235:genetics* / Q000378:metabolism; D013912:Threonine / Q000235:genetics; D014162:Transfection / Q000379:methods
D044402:Receptor, Serotonin, 5-HT2A; D013912:Threonine; D015500:Chloramphenicol O-Acetyltransferase; D003545:Cysteine; D000409:Alanine; D005998:Glycine