A-T specific DNA ligands and hypotonic induced supercondensation of chromocentre in brain cells of Drosophila nasuta larvae in relation to their synthetic activities
Roy, J.K.; Lakhotia, S.C.
Indian Journal of Experimental Biology 22(6): 287-291
1984
ISSN/ISBN: 0019-5189 PMID: 6210246 Document Number: 226396
When A-T [adenosine-thymidine] base specific DNA ligands like Hoechst 33258 (H) or distamycin A (DA)treated brain ganglia of D. nasuta larvae are exposed to a pre-fixation hypotonic (hy) solution, the heterochromatic chromocenter (cc) becomes supercondensed in 40-60% interphase nuclei. The effects of these DNA ligands on DNA and RNA synthesis in larval brain ganglia and the relationship of cc supercondensation with these synthetic activities of a cell were examined by autoradiography. Both the frequency of replicating cells and the rate of 3H-thymidine uptake are inhibited by the treatment, more so in the population of cells in which the cc is supercondensed. H treatment has no effect on the rate of 3H-uridine uptake in transcribing nuclei although, compared to the control ganglia, the frequency of labeled nuclei is reduced after treatment. The cc supercondensation is shown to occur preferentially in nuclei which are active in DNA and/or RNA synthesis.