Structural analysis and expression of the human thrombospondin gene promoter.

We have isolated a 34-kilobase pair genomic thrombospondin clone and determined the sequence of 2033 base pairs of the 5'-flanking region, the first entirely untranslated exon and the first intron. A number of interesting regulatory motifs were identified. The transcription start site, determined by primer extension and S1 nuclease analysis, was shown to be 20-30 bases 3' of a TATA-like sequence, TTTAAAA. We have also shown that a thrombospondin promoter-bovine growth hormone fusion gene is transcribed in transiently transfected cells. We conclude that the genomic clone contains the transcriptional signals of the thrombospondin gene and will therefore be useful in the analysis of cis-acting elements that regulate the expression of this gene.