Analysis of the chromosomal DNA replication pattern using the bromodeoxyuridine labeling method.

The DNA replication of human lymphocytes was studied using the labeling pattern on chromosomes after pulse labeling with bromodeoxyuridine and immunostaining with the monoclonal antibody to bromodeoxyuridine. The sites of bromodeoxyuridine incorporation were defined by comparison with the same karyotype treated G-banding, and a more precise analysis was performed using the image analyzer, Maziscan III. Early phase DNA synthesis roughly coincided with R-bands and late phase DNA synthesis with G-bands. One case of acute myeloid leukemia which developed from myelodysplastic syndrome, had a 46,XY, t(4;11) (p12;p15) karyotype, and revealed an altered DNA replication time at the translocated site, 4p15, from the late to the early phase. The present method was useful in detecting an alteration of DNA replication timing according to chromosomal translocation.