Structure and sequence of the human c-sis/platelet-derived growth factor 2 (SIS/PDGF2) transcriptional unit

The structure of the normal human c-sis/platelet-derived growth factor 2 (SIS/PDGF2) transcript was determined by a combination of cDNA cloning, nuclease S1 mapping, and primer extension. Nucleotide sequence analysis revealed that the 3373-nucleotide SIS/PDGF2 mRNA contained only a 723-base-pair (bp) coding sequence for the PDGF2 precursor polypeptide. The coding sequence was flanked by long 5' (1022 bp) and 3' (1625 bp) untranslated regions. The 5' noncoding region, as well as upstream flanking genomic sequences, contained clusters of specific short repeat sequences. A consensus transcriptional promoter sequence, TATAAA, was identified 24 bp upstream of the mRNA start site and an enhancer-like "TG element" was detected about 180 bp downstream from the site of polyadenylylation. These findings identify putative regulatory elements of the SIS/PDGF2 gene.