CHARACTERIZATION OF HUMAN BONE MARROW-DERIVED CLOSED CIRCULAR DNA CLONES

Because of interest in mechanisms of recombination involved in chromos omal deletions in neoplastic disease, and their relation to possible r earrangements in normal tissues, we are studying circular DNA molecule s from human tissue with a long-term goal of investigating them as pos sible by-products of physiologically relevant intrachromosomal recombi nation events. Covalently closed circular (ccc) DNA from human bone ma rrow was cloned in bacteriophage vectors, and fourteen clones chosen r andomly from the cccDNA-derived library were characterized. Five clone s originated from chromosome-specific centromeric alpha-satellite DNA; two clones carried highly repetitive sequences probably derived from interspersed repetitive elements; six clones were derived from single- copy chromosome-specific sequences which detected homologous rodent se quences; and one clone (EPM 10) was derived from a small chromosome 11 -specific sequence family which localized to chromosome regions 11cen and 11q14. Oligonucleotide primers derived from the cccDNA clones were used in polymerase chain reaction studies to show that (1) the EPM10 clone carried the circular junction, (2) several of the single-copy pr oducts could be detected in three different bone marrow cccDNA prepara tions, and (3) the Alu-PCR profile for bone marrow cccDNA showed disti nct bands which were similar in four bone marrow cccDNA preparations.