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|Title:||Further observations on hoechst 33258 plus hypotonic treatment induced supercondensation of interphase heterochromatin in Drosophila nasuta cells|
|Author:||Roy, J K|
Lakhotia, S C
Mello, M L S
|Abstract:||Extending our earlier observation [Exp Cell Res, 132(1981) 423] on the effects ofHoechst 33258 and hypotonic treatments on condensation ofheterochromatin in interphase nuclei of D. nasuta, we now show by Feulgen-DNA cytophotometry that the chrornocentreheterochrornatin in Hoechst 33258+hypotonic treated interphase cells of D. nasuta issupercondensed. Like the Hoechst 33258 effect, exposure of live embryonic (2 hr) or larval brain cells (16 hr) of D. nasuta to 20 Jlgjml Netropsin or Distamycin A (both A-T specific DNA ligands) when followed by a pre-fixation hypotonic treatment, also causes supercondensation of chromocentre in majority of the treated cells; without the hypotonic treatment chromocentre is not supercondensed in any ofthe drug treated cells. A G-C specific DNA ligand, Olivomycin, does not cause any such effect. lt is suggested that, only A-T specific ligandscan cause the supercondensation of interphase heterochromatin when the treated ceJls are exposed to hypotonic solution prior to fixation. By reverting 16hr Hoechst 33258+ 15min hypotonic treated larval brain ganglia to isotonic cuIture medium for I or 4 hr, thesupercondensation of chromocentre can be reversed, although a second hypotonic treatment after 4 hr in Hoechst 33258 free isotonic culture medium restores the supercondensation of chromocentre. It appears that the A-T specific drug binding to DNA modifies the nucleoprotein interactions in interphase heterochromatin in such a way that a hypotonic treatment causes a very rapid but reversible reorganization of ch~omatin constituents 10 cause the supercondensation.|
|Editor:||Council for Scientific and Industrial Research|
|Citation:||Indian Journal Of Experimental Biology. Council Scientific Industrial Research, v. 20, n. 11, n. 791, n. 796, 1982.|
|Appears in Collections:||IB - Artigos e Outros Documentos|
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