[Actin localization in the nuclei of two-cell mouse embryos]

In this study, preimplantation mouse embryos were used as a new model for investigation of actin distribution in the nuclei and identification of functional forms of intranuclear actin. Combination of direct detection of actin by fluorescent-conjugated falloidin and DNase I with the method of indirect immunofluorescence was applied as an integrated approach to study localization of actin in the nuclei of two-cell mouse embryos. Monomeric actin and two oligomeric forms of actin were detected in the nuclei, and each of these forms demonstrated its own pattern of distribution. Oligomeric actin recognized by antibodies to C-terminal domain of actin was associated with condensed chromatin as well as with metaphase chromosomes and chromatin of second polar body. Monomeric actin and another oligomeric form recognized by antibodies to N-terminal domain were revealed in the area of dispersed chromatin localization.