COMPARISON OF THE 5'-FLANKING SEQUENCES OF THE HUMAN AND BOVINE VON-WILLEBRAND FACTOR-ENCODING GENES REVEALS ALTERNATION OF HIGHLY HOMOLOGOUS DOMAINS WITH SPECIES-SPECIFIC ALU-TYPE REPEATS

von Willebrand factor (vWF), a multimeric glycoprotein important for h emostasis, is specifically synthesized in endothelial cells and in pla telet precursors (megakaryocytes), Recent studies from two laboratorie s, including ours, were published regarding the cell-specific transcri ption of reporter genes controlled by the human (hu) VWF promoter in t ransfected bovine (be) endothelial cells and cells of non-endothelial origins. In order to verify that the regulatory domains previously cha racterized in the 5' region of hu VWF are also present in bo VWF, we h ave sequenced 1.9 kb upstream from the cap site, plus five exons. The comparison of human and bovine exons two to five shows homology of 83% at the nucleotide (nt) level and 78% at the deduced amino-acid sequen ce level. The bovine and human exons one, which are non-coding and spa n 233 and 250 bp, respectively, are only 64% homologous. In the first exon, potentially involved in endothelial-cell-specific transcription, the binding site for factor Sp1 is present in bo VWF, whereas the GAT A sequence is replaced by a GACA sequence. The sequence corresponding to the human basal promoter, located between nt -89 and +19, is well c onserved with 82% homology. However, the human TAATTA sequence (at nt -32) considered to be a TATA box, is replaced by TCATTA, and the CCAAT element at nt -18 is replaced by CCTGT. Among domains involved in tra nscription, the negative regulatory domain located 5' from the core pr omoter is highly conserved. The bovine sequence upstream from the firs t intron can be aligned with the human sequence up to nt -656 which is located in a polymorphic poly(GT)(18-26) sequence. At this site, the bovine DNA contains an insertion of 523 bp which corresponds to a bovi ne Alu-type art2 repeat of 331 bp flanked by bovine microsatellites. T he art2 sequence is an Alu-type repeat in artiodactyls with at least 1 00 000 copies in the bovine genome. Upstream from this insertion, 368 bp of the bovine sequence can be aligned with the human counterpart up to a 9-bp element which flanks an human Alu repeat which is absent fr om the bovine DNA. Upstream of the human Alu insertion and a duplicate of the 9-bp element, the two sequences are again homologous.