Shanghai Institute of Materia Medica;
Chinese Academy of Sciences;
Shanghai Institute of Materia Medica;
Chinese Academy of Sciencesnduction of c-myc gene amplification in L1210 cells by hydroxyurea and its inhibition by homohar-ringtonine were investigated using the DNA-DNA molecular hybridization technique. When the cells were treated with hydroxyurea 1.0 mM for 16 hours;
and incubated a further 16 hours in a drug-free medium;
the c-myc gene amplified 23.5-fold. If homohar-ringtonine 50 μM was used at the same time as hydroxyurea;
gene amplification did not occur. Cycloheximide;
an inhibitor of protein biosynthesis;
produced a similar effect. Our results indicated that a (or some) protein factor(s) might be involved in gene amplification. Detailed analysis showed that the synthesis of this protein factor(s) started 4 hours before the initiation of the S phase but did not continue in the S phase. It was also found that this protein factor(s) was very labile and began to degrade 2 hours after its appearance.;
amplification; biosynthesis; degrade; Induction; DNA; initiation; EcoRI; incubated; hydrox; appearance;