A 413 BP REGION UPSTREAM THE HUMAN 5-HT1A RECEPTOR GENE IS SUFFICIENTFOR ITS IN-VITRO EXPRESSION

The regulation of a specific pattern of neuronal 5-hydroxytryptamine-( 1A) (5-HT1A) receptor gene expression in the brain is hardly understoo d. Identification of cis-acting DNA sequences that control expression of the human 5-HT1A receptor gene has been undertaken by fusion of a 4 13 base pairs (bp)-long DNA segment upstream the human 5-HT1A receptor gene start codon to the 5-HT1A receptor gene. When this fusion produc t was inserted into the expression vector pcDNA3 and transfected into Cos-7 cells, it was shown to drive expression of specific [H-3] (+/-)- 8-hydroxy-2-(di-n-propylamino)tetralin ([H-3] 8-OH-DPAT) binding sites with a K-d of 1.18 nM and a B-max of 105 fmol/mg protein. The yield o f expression of [H-3] 8-OH-DPAT binding sites by fusion of the 5-HT1A receptor gene to strong promoters, such as the Rous sarcoma virus long terminal repeat and the cytomegalovirus promoter, was 2.5 to 8 times greater. The pharmacological binding profile of these [H-3] 8-OH-DPAT binding sites was similar to that of cloned human 5-HT1A receptors sta bly expressed in HeLa cells. The importance of an Initiator sequence a nd regulatory Spl sites in the 413 bp region to direct transcription o f the human 5-HT1A receptor gene is discussed.