The subcortical maternal complex protein Nlrp4f is involved in cytoplasmic lattice formation and organelle distribution

Abstract

In mammalian oocytes and embryos, the subcortical maternal complex (SCMC) and cytoplasmic lattices (CPLs) are two closely related structures. Their detailed compositions and functions remain largely unclear. Here, we characterize Nlrp4f as a novel component associated with the SCMC and CPLs. Disruption of maternal Nlrp4f leads to decreased fecundity and delayed preimplantation development in the mouse. Lack of Nlrp4f affects organelle distribution in mouse oocytes and early embryos. Depletion of Nlrp4f disrupts CPL formation but does not affect the interactions of other SCMC proteins. Interestingly, the loss of Khdc3 or Tle6, two other SCMC proteins, also disrupts CPL formation in mouse oocytes. Thus, the absence of CPLs and aberrant distribution of organelles in the oocytes caused by disruption of the examined SCMC genes, including previously reported Zbed3, Nlrp5, Ooep and Padi6, indicate that the SCMC is required for CPL formation and organelle distribution. Consistent with the role of the SCMC in CPL formation, the SCMC forms before CPLs during mouse oogenesis. Together, our results suggest that the SCMC protein Nlrp4f is involved in CPL formation and organelle distribution in mouse oocytes.

Keywords: Cytoplasmic lattices; Maternal effect gene; NLRP; Oocyte-to-embryo transition; Organelle; SCMC.