Complete nucleotide sequence of the gene for human heparin cofactor II and mapping to chromosomal band 22q11.

Heparin cofactor II (HCII) is a 66-kDa plasma glycoprotein that inhibits thrombin rapidly in the presence of dermatan sulfate or heparin. Clones comprising the entire HCII gene were isolated from a human leukocyte genomic library in EMBL-3 lambda phage. The sequence of the gene was determined on both strands of DNA (15,849 bp) and included 1749 bp of 5'-flanking sequence, five exons, four introns, and 476 bp of DNA 3' to the polyadenylation site. Ten complete and one partial Alu repeats were identified in the introns and 5'-flanking region. The HCII gene was regionally mapped on chromosome 22 using rodent-human somatic cell hybrids, carrying only parts of human chromosome 22, and the chronic myelogenous leukemia cell line K562. With the cDNA probe HCII7.2, containing the entire coding region of the gene, the HCII gene was shown to be amplified 10-20-fold in K562 cells by Southern analysis and in situ hybridization. From these data, we concluded that the HCII gene is localized on the chromosomal band 22q11 proximal to the breakpoint cluster region (BCR). Analysis by pulsed-field gel electrophoresis indicated that the amplified HCII gene in K562 cells maps at least 2 Mbp proximal to BCR-1. Furthermore, the HCII7.2 cDNA probe detected two frequent restriction fragment length polymorphisms with the restriction enzymes BamHI and HindIII.