Cloning and characterization of the gene encoding the mouse beta 2-glycoprotein I

beta 2-Glycoprotein I, a serum protein with in vitro anticoagulant properties, plays a vital role in the binding of "anticardiolipin" antibodies purified from patients with autoimmune disease in a cardiolipin ELISA. The gene (ApoH) encoding the mouse beta 2-glycoprotein I, including 5' and 3' flanking sequences, has been isolated and characterized. The gene covers approximately 18 kb and consists of eight exons. We demonstrate that the gene is present in a single copy in the mouse genome. The exon/intron structure was elucidated by nucleotide sequencing and restriction enzyme mapping. The exon/intron splice junction sites follow the gt/ag consensus sequence rule. The transcription start site was identified by primer extension 44 nucleotides upstream of the initiator AUG codon. beta 2-Glycoprotein I consists of repeated domains that correspond well to the exon/intron structure of the gene.