MAPPING OF REPLICATION ORIGINS AND TERMINATION SITES IN THE DUCHENNE MUSCULAR-DYSTROPHY GENE

The replication structure of the human dystrophin gene in cultured mas culine erythroleukemia cells (line HEL 92.1.7) was studied using the r eplication direction assay. This gene is organized into at least six r eplicons ranging in size from 170 to more than 500 kb. One of the repl icon junctions (sites of replication termination) was mapped to intron 44, i.e., roughly in the same area where the major recombination hot spot is located. A replicon junction was also found between the muscle and the brain promoters. The two replicons mapped in the present stud y are highly asymmetric, as the distances covered by the replication f orks moving in opposite directions from the same origin differ by more than threefold. (C) 1997 Academic Press.