THE KARYOSPHERE CAPSULE IN OOCYTES OF HIBERNATING FROGS RANA TEMPORARIA CONTAINS ACTIN, LAMINS AND SMALL NUCLEAR RNP.

: The nuclei of late vitellogenic oocytes of hibernating frogs Rana temporaria were studied. During the studied period of oogenesis, chromosomes are significantly inactivated and surrounded by a fibrillar karyosphere capsule. Formation of the karyosphere capsule in the grass frog oocytes was previously investigated in detail at the light and electron microscopic levels, but the molecular composition of the capsule still remains uncertain. Immunofluorescent staining of whole-mount preparations of oocyte nuclei revealed the following proteins in the karyosphere capsule: actin, lamins A, C and B, and the Sm proteins of snRNPs. A putative role of these proteins in formation of the karyosphere capsule is discussed.