CAJAL BODIES IN INSECT OOCYTES. II. NEW DATA ON THE MOLECULAR COMPOSITION OF CAJAL BODIES IN OOCYTES OF THE HOUSE
CRICKET ACHETA DOMESTICUS WITH SPECIAL REFERENCE TO INTERACTIONS BETWEEN CAJAL BODIES AND INTERCHROMATIN
GRANULE CLUSTERS
I. S. Stepanova, D. S. Bogolyubov,1 V. N. Parfenov
Institute of Cytology RAS, St. Petersburg;
1 e-mail: dmitr@mail.cytspb.rssi.ru
Cajal bodies (CBs) in oocytes of the house cricket Acheta domesticus are large, perfectly spherical nuclear
organelles with a complex internal structure. These consist of a fibrillar coilin-containing matrix and a central
cavity with a prominent fibrogranular body inside; the latter has been referred to as an "internal" interchromatin
granule cluster (IGC). Within the matrix of CBs we detected transcriptional co-activators CBP/p300 and TATA-box
binding protein (TBP). No RNA polymerase II was revealed in CBs of both normal and actynomycin D treated oocytes.
In the nucleoplasm of A. domesticus oocytes, besides CBs, free IGCs were observed. In oocytes treated with
actynomycin D, the amount of "free" IGCs in the nucleoplasm increase significantly, granular and fibrillar components
of IGCs were seen segregated, and RNA polymerase II and CBP/p300 were found to be accumulated in fibrillar zones of
IGCs.
Key words: insects, oocyte nucleus, Cajal bodies, interchromatin granule clusters, laser confocal
and immunogold electron microscopy, actynomycin D
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