Cytogenetic replication studies on murine T-cell leukemias with special consideration to chromosome 15.

Chromosomal replication was studied by means of the BrdU-Höchst-Giemsa-technique in three minute T-cell leukemias with special regard to chromosome 15. In all the three leukemic cell lines the normally early replicating band 15 E was undetectable whereas late replication in this region is completely unaltered. Furthermore, R-banding, the structural homologue of early replication banding, remains unchanged. This observation is interpreted as a shift in the time point of replication during the S-phase of region 15 E, though the exact timing of replication of this region in tumor chromosomes remains unresolved.