Construction of the nuclear matrix at the transition from maternal to zygotic control of development in the mouse: an immunocytochemical study.

The nuclear matrix is thought to be responsible for DNA organization, DNA replication, RNA synthesis, and RNA processing. We have looked for the presence of nuclear matrix antigens during early mouse embryogenesis. Antibodies to peripheral and interior antigens (P1, Pl1, Pl2, and lamin B) were used to immunolocalize nuclear matrix antigens in germinal vesicle oocytes, metaphase II oocytes, zygotes, two-cell-stage embryos, and eight-cell stage embryos. All antibodies reacted with the nuclei of germinal vesicle oocytes, and two- and eight-cell-stage embryos; however, only P1 and lamin B were present at the pronuclear stage. In eggs collected at the pronuclear stage and cultured to the late two-cell stage in the presence of alpha-amanitin, the matrix morphology was altered for Pl1 and Pl2. alpha-Amanitin had no affect on the distribution of P1 or lamin B antigens. If alpha-amanitin was added 2 hr after cleavage to the two-cell stage, the normal staining pattern of Pl2 was retained. These results suggest that the presence of specific components of an internal matrix is correlated with normal genomic activity.