Molecular basis of oocyte cytoplasmic lattice assembly - PubMed

6 hours ago

Mammalian oocytes contain a fibric structure called the cytoplasmic lattice (CPL), crucial for oocyte maturation and early embryonic development.
CPL consists of the subcortical maternal complex (SCMC) and multiple components, including PADI6.
The cryo-EM structure of CPL from mouse oocytes reveals 14 constitutive protein subunits and a filamentous architecture with repeating 'U-shaped basket' (UB) and 'adapter ring' (AR) units.
AR has a two-fold symmetric conformation with two NLRP4f, four SCMC, and two ZBED3 subunits, circularized via two distinct interaction clusters.
UB is anchored by PADI6, a didecamer composed of ten homodimers assembled by two back-to-back pentamers, forming the lateral side of UB.
The UB structure includes underfoot base and up-down sides formed by central-symmetric assemblies (UBE2D3-UHRF1-NLRP14) and (TUBB2B-TUBB2A-FBXW24-SKP1), respectively.
Two SCMC dimers within each AR connect the up and down sides of adjacent UBs, maintaining the repetitive connection between neighboring CPL units.
This study provides insights into the architectural principles of CPL assembly, aiding understanding of its roles in early embryogenesis and female reproductive disorders.

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