title: Genomic DNA breakpoints in AML1/RUNX1 and ETO cluster with topoisomerase II DNA cleavage and DNase I hypersensitive sites in t(8;21) leukemia.
abstract: The translocation t(8;21)(q22;q22) is one of the most frequent chromosome translocations in acute myeloid leukemia (AML). AML1/RUNX1 at 21q22 is involved in t(8;21), t(3;21), and t(16;21) in de novo and therapy-related AML and myelodysplastic syndrome as well as in t(12;21) in childhood B cell acute lymphoblastic leukemia. Although DNA breakpoints in AML1 and ETO (at 8q22) cluster in a few introns, the mechanisms of DNA recombination resulting in t(8;21) are unknown. The correlation of specific chromatin structural elements, i.e., topoisomerase II (topo II) DNA cleavage sites, DNase I hypersensitive sites, and scaffold-associated regions, which have been implicated in chromosome recombination with genomic DNA breakpoints in AML1 and ETO in t(8;21) is unknown. The breakpoints in AML1 and ETO were clustered in the Kasumi 1 cell line and in 31 leukemia patients with t(8;21); all except one had de novo AML. Sequencing of the breakpoint junctions revealed no common DNA motif; however, deletions, duplications, microhomologies, and nontemplate DNA were found. Ten in vivo topo II DNA cleavage sites were mapped in AML1, including three in intron 5 and seven in intron 7a, and two were in intron 1b of ETO. All strong topo II sites colocalized with DNase I hypersensitive sites and thus represent open chromatin regions. These sites correlated with genomic DNA breakpoints in both AML1 and ETO, thus implicating them in the de novo 8;21 translocation.
authors.affiliation: Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago, IL 60637, USA.
authors.forename: Yanming
authors.initials: Y
authors.lastname: Zhang
authors.forename: Pamela
authors.initials: P
authors.lastname: Strissel
authors.forename: Reiner
authors.initials: R
authors.lastname: Strick
authors.forename: Jianjun
authors.initials: J
authors.lastname: Chen
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Nucifora
authors.forename: Michelle M
authors.initials: MM
authors.lastname: Le Beau
authors.forename: Richard A
authors.initials: RA
authors.lastname: Larson
authors.forename: Janet D
authors.initials: JD
authors.lastname: Rowley
mesh_terms: D000328:Adult; D000368:Aged; D001665:Binding Sites; D002648:Child; D002891:Chromosomes, Human, Pair 21; D002898:Chromosomes, Human, Pair 8; D003001:Cloning, Molecular; D050676:Core Binding Factor Alpha 2 Subunit; D004250:DNA Topoisomerases, Type II / Q000378:metabolism*; D004273:DNA, Neoplasm / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics*; D003850:Deoxyribonuclease I / Q000378:metabolism*; D005260:Female; D006801:Humans; D007951:Leukemia, Myeloid / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D005810:Multigene Family; D009363:Neoplasm Proteins / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D000075142:RUNX1 Translocation Partner 1 Protein; D014157:Transcription Factors / Q000235:genetics*; D014178:Translocation, Genetic; D014407:Tumor Cells, Cultured
chemical_list: D050676:Core Binding Factor Alpha 2 Subunit; D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D000075142:RUNX1 Translocation Partner 1 Protein; C493728:RUNX1 protein, human; C082222:RUNX1T1 protein, human; D014157:Transcription Factors; D003850:Deoxyribonuclease I; D004250:DNA Topoisomerases, Type II