NUCLEAR PROTEINS DURING THE ONSET OF CELL-PROLIFERATION IN PEA ROOT-MERISTEMS

The DNA: proteins ratio in nuclei of root meristems of pea (Pisum sativum L. cv. Lincoln) changed considerably during germination as cells moved from a quiescent to an actively proliferating state with a higher protein content in nuclei of the latter. Electrophoretic patterns of nuclear proteins extracted at different times of germination were used to examine qualitative changes. The various patterns presented a substantial similarity but there were some proteins whose content increased or decreased and others which disappeared or appeared during germination. The bulk of these variations occurred between 24 and 48 h of germination, suggesting that they might be correlated to the transition from quiescence to the proliferating state. The pattern of nuclear proteins obtained from adult differentiated root tissue was also examined. We tried to purify five different nuclear protein components from intact nuclei by a multi-step extraction procedure using a series of different buffers to ascertain the nature of proteins presenting major interesting variations. Most of these proteins purified with the nuclear sap or ribosomal components.