KARYOSPHERE AND EXTRACHROMOSOMAL NUCLEAR BODIES IN OOCYTES OF THE SCORPIONFLY,
PANORPA COMMUNIS
F. M. Batalova, D. S. Bogolyubov, V. N. Parfenov
Institute of Cytology, RAS, St. Petersburg, Russia;
e-mail: florina@mail.cytspb.rssi.ru
Oocyte nuclear structures were studied for the scorpionfly Panorpa communis at different stages of
oocyte growth, from pachytene to the first meiotic division. Using immunofluorescent and immunogold microscopy, we analyzed the
nuclear distribution of RNA polymerase II, splicing factors and coilin. These factors were revealed in close association with
perichromatin fibrils and, later, with some elements of the karyosphere and extrac-hromosomal nuclear bodies (NBs). Besides, it
was shown that large amounts of P. communis oocyte NBs represent Cajal bodies (CBs) and contain CB marker protein, coilin,
as well as RNA polymerase II, and in some cases an essential splicing factor, SC35. The presence of SC35 is commonly not
characteristic of CBs in somatic cells. CB dynamics was traced in inactivated oocyte nuclei, during a gradual condensation of
chromosomes and their final assembling into the karyosphere. It has been shown that coilin, RNA polymerase II and SC35 protein
are common compounds shared by CBs and some granular material associated with these condensed chromosomes. CB remnants were
demonstrated in the ooplasm after the breakdown of nuclear envelope before the first meiotic division. In inactivated oocyte
nuclei, CBs serve presumably as storage compartments for some inactive components essential for gene expression.
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