Structure, organization, and transcription units of the human α-platelet-derived growth factor receptor gene, PDGFRA

Isolation and characterization of genomic clones encoding human α-platelet derived growth factor receptor (HGMW-approved symbol PDGFRA) revealed that the gene spans approximately 65 kb and contains 23 exons. The 5′-untranslated region of the mRNA is encoded by exon 1, and a large intron of 23 kb separates exon 2 encoding the translation initiator codon AUG and the signal sequence. The locations of exon/intron boundaries in the extracellular immunoglobulin-like domains, the transmembrane domain, the two cytoplasmic tyrosine kinase domains, and the kinase insertion domain are very similar to those in c-kit and macrophage colony stimulating factor-1 receptor genes. The transcription start site was mapped to a position 393 bp upstream of the AUG translation initiator codon by S1 mapping and primer extension analysis. The 5′-flanking region of the gene lacks a typical TATA box but contains a typical CCAAT box and GATA motifs. This region also contains potential sites for AP-1, AP-2, Oct-1, Oct-2, and Sp1. The 5′-flanking region of the gene was fused to the luciferase reporter gene, and transcription units of the gene were determined.