Amplification of nuclear DNA sequences during induced plant cell dedifferentiation.

Cell dedifferentiation has been induced in Vicia faba roots by removing the whole meristem (decapitation). When centrifuged to equilibrium in CsCl density gradient, the DNA from dedifferentiating tissues forms a heavier satellite, not occurring in the DNA from differentiated tissues. Most of the radioactivity after [3H]thymidine feeding is found in the satellite DNA. Its sequences have a well defined nuclear localization, as shown by in situ hybridization experiments. These results indicate amplification of G + C-rich nuclear DNA sequences during cell dedifferentiation.