CHARACTERIZATION OF THE HUMAN PLATELET ENDOTHELIAL-CELL ADHESION MOLECULE-1 PROMOTER - IDENTIFICATION OF A GATA-2 BINDING-ELEMENT REQUIRED FOR OPTIMAL TRANSCRIPTIONAL ACTIVITY

Platelet/endothelial cell adhesion molecule-1 (PECAM-1) is a 130-kD me mber of the Ig gene superfamily that is expressed on platelets, endoth elial cells, and certain leukocyte subsets. To examine the factors con trolling vascular-specific expression of PECAM-1, we cloned the 5'-fla nking region of the PECAM-1 gene and analyzed its transcriptional acti vity. 5'-Rapid amplification of cDNA ends (5'-RACE) analysis showed th at transcription initiation occurred at several closely spaced nearby sites originating approximately 204 bp upstream from the translation s tart site. Analysis of the sequence immediately upstream from the tran scription initiation site (TIS) showed no canonical TATA or CAAT eleme nts, however an initiator element commonly found in TATA-less promoter s encompassed the TIS. 5'-serially truncated PECAM-1 promoter segments cloned in front of a luciferase reporter drove transcription in both a lineage- and orientation-specific manner. Putative cis-acting contro l elements present within a 300-bp core promoter included two ets site s, an Spl site, tandem E-box domains, two GATA-associated sites (CACCC ), an AP-2 binding site, and a GATA element at -24. Mutational analysi s showed that optimal transcriptional activity required the GATA seque nce at position -24, and gel-shift assays further showed that the GATA -2 transcription factor, but not GATA-1, bound to this region of the P ECAM-1 promoter, Understanding the cis- and transacting factors that r egulate the tissue-specific expression of PECAM-1 should increase our understanding of the mechanisms by which vascular-specific gene expres sion is achieved. (C) 1997 by The American Society of Hematology.