NUCLEAR PROTEIN MATRIX FROM GIANT NUCLEI OF CHIRONOMUS PLUMOSUS
DETERMINATES POLYTHENE CHROMOSOME ORGANIZATION
M. S. Makarov, Yu. S. Chentsov
M. V. Lomonosov Moscow State University;
e-mail: mcsimmc@yandex.ru, yuchentsov@mail.ru
Giant nuclei from salivary glands of Chironomus plumosus were treated in situ with detergent, 2 M NaCl
and nucleases in order to reveal residual nuclear matrix proteins (NMP). It was shown, that preceding stabilization
of non-histone proteins with 2 mM CuCl2 allowed to visualize the structure of polythene chromosomes at
every stage of the extraction of histones and DNA. Stabilized NPM of polythene chromosomes maintains their
morphology and banding patterns, which is observed by light and electron microscopy, whereas internal fibril
net or residual nucleoli are not found. In stabilized NPM of polythene chromosomes, topoisomerase IIa and
SMC1 retain their localization that is typical of untreated chromosomes. NPM of polythene chromosomes also
includes sites of DNA replication, visualized with BrDU incubation, and some RNA-components. So, we can
conclude that structure of NPM from giant nuclei is equal to NPM from normal interphase nuclei, and that morphological
features of polythene chromosomes depend on the presence of NMP.
Key words: polythene chromosome, non-histone proteins, nuclear protein matrix, stabilization, topoisomerase IIα, SMC1
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