Khdc1b, a member of a small family of KH-domain containing proteins specific to eutherian mammals, is closely related to Khdc1a. It is specifically expressed in mouse oocytes and early embryos. KHDC1B may function as a translational regulator, potentially via its interaction with the mouse translational regulator cytoplasmic polyadenylation binding protein 1 (mCPEB1), to regulate the translation of mRNA targets required for oocyte maturation [1].

In Xenopus embryos, expression of KHDC1B led to cleavage arrest, a phenotype that was rescued by co-expression of mCPEB1. Co-immunoprecipitation and co-immunostaining experiments confirmed the functional interaction between KHDC1B and mCPEB1. Also, KHDC1B levels and its binding partners were shown to fluctuate with the cell cycle [1].

In conclusion, KHDC1B is a key translational regulator in oocyte maturation. The study of KHDC1B in model organisms like Xenopus embryos has provided insights into its function in regulating early embryonic development, potentially offering a better understanding of the molecular mechanisms underlying human infertility and ovarian germ cell tumors.