passages.id: split_1_test_1753_passage
passages.type: progene_text
passages.text: Characterization of the genomic organization and structure of the human ABCG1 gene demonstrates that : (i) the gene consists of 23 exons spanning 98 kilobase pairs ( kb ) on chromosome 21q22.3 , (ii) the 203 amino acids are encoded on three previously unidentified exons , 8-10 , and (iii) a promoter , containing a TATA box and two liver X receptor ( LXR ) alpha response elements ( LXREs ) , is located upstream of exon 8 .