3H-URIDINE INCORPORATION IN THE PREMITOTIC STAGE OF RHIZOID CELL DIFFERENTIATION IN PTERIS VITTATA L. |
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| Authors: | David Cohen William J Crotty |
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| Institution: | Department of Biology, Long Island University, Brooklyn, New York, 11201
Department of Biology, New York University, New York, 10003 |
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| Abstract: | The premitotic rhizoid stage (corona stage) of P. vittata gametophytes was pulsed in radioactive uridine for 5, 15, or 30 min and the data analyzed quantitatively by autoradiography. After 5 min, only the nucleoplasmic compartment is labelled significantly, suggesting that this short pulse is insufficient time for labelled precursor to be fixed in the nucleolus or to be transported from the nucleus to the cytoplasm. Since after 15 and 30 min, all compartments are labelled, with the greatest proportional increase over the nucleolus, it is concluded that cytoplasmic labelling is nuclear in origin and that nucleolar RNA activity is relatively high in this stage. |
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