We characterized N-myc gene amplification in three human neuroblastoma cell lines (IMR-32, TGW, GOTO). Rearrangements in long-range regions surrounding amplified N-myc genes were examined by pulsed-field gel electrophoresis. Since rare-cutting enzymes completely digested DNA at the middle of the N-myc gene, we were able to construct a physical map upstream and downstream of the germline N-myc gene, and to obtain information on restriction sites surrounding amplified N-myc genes. This method enables us to envisage the organization of amplified units over a long range. Digestion patterns differed considerably among the germline and the three cell lines, but were simple in each case. We estimated that the minimal distance between neighboring N-myc genes is at least several hundred kilobases. Our data suggest that amplification units contain several DNA fragments derived from ditterent loci, but that they are homogeneous.
All Science Journal Classification (ASJC) codes
- Structural Biology
- Molecular Biology
- Cell Biology