Chromosomal localization of a sequence with in vivo activity for initiation of DNA replication

The genomic fragment containing the sequence of human cDNA clone 343, previously characterized as capable of autonomous replication upon transfection into mammalians cells and occupying a genomic region inclusive of an initiation zone for DNA replication, was mapped on human chromosome 6q22-qter by a combination of in situ hybridization and G-banding. Southern blot hybridization with a penl of human-hamster somatic cells confirmed the location of the 343 gene on chromosome 6. Fragile sites have been mapped to the region at 6q21 and 6q26. Several neoplastic disorders, including melanoma, acute nonlymphocytic leukemia, acute lymphocytic leukemia, and malignant lymphoma, have also exhibited translocations and deletions involving the region 6q21–6q27.