| Previously, our laboratory isolated a cDNA encoding a 17kDa protein with sequence similarity to Mob1 (Wang, 2001), a conserved protein that plays a role in exit from mitosis in yeast. Although crude antiserum against this protein recognized a 17kDa protein in Xenopus oocytes and eggs, a combination of immunoblot analysis, antibody neutralization experiments, and nucleotide sequence analysis, showed that this cDNA is a truncated form of Xenopus Mob1B1, which encodes a full length protein of approximately 30kDa. This protein does not undergo obvious changes in abundance or electrophoretic mobility during oocyte maturation that were detectable by immunoblotting. Using anti-peptide antibodies against two human Mob1-related proteins, Mob1A could not be detected in oocyte, eggs or embryos, whereas a candidate for Mob1C was found in all three samples. These studies provide a foundation for future experiments examining the function of Mob1-related proteins in oocyte maturation and in the cell cycles of the early embryo. |
