GENOMIC ORGANIZATION AND CHROMOSOMAL LOCALIZATION OF THE GENE ENCODING HUMAN P-SELECTIN GLYCOPROTEIN LIGAND

The gene for P-selectin glycoprotein ligand (PSGL-1) has been cloned f rom a human placenta genomic DNA library. A single intron of approxima tely 9 kilobases was found in the 5'-untranslated region and the compl ete coding region resides in exon 2. The genomic clone differs from th e cDNA clone isolated from HL-60 cells in that it encodes an extra cop y of the decameric repeat located in the extracellular domain of PSGL- 1, Further analysis indicated that the PSGL-1 genes of HL-60 and U-937 cells contain 15 repeats, whereas the PSGL-1 genes of polymorphonucle ar leukocytes, monocytes, and several other cell lines contain 16 repe ats. Transfection experiments did not indicate a functional difference between these two variants of PSGL-1. The two previously observed PSG L-1 mRNA species of 2.5 and 4 kilobases most likely arise from differe ntial utilization of polyadenylation signal sequences. The organizatio n of the PSGL-1 gene closely resembles those of CD43 and human platele t glycoprotein GPIb alpha, both of which have an intron in the 5'-nonc oding region, a long second exon containing the complete coding region , and TATA-less promoters. The gene for human PSGL-1, which has been d esignated SELPLG by the Human Gene Nomenclature Committee, was mapped to chromosome 12q24 using Southern blot analysis of DNA from a set of human-mouse cell hybrids, and fluorescent in situ hybridization on met aphase chromosome spreads.