Potential Role for MATER in Cytoplasmic Lattice Formation in Murine Oocytes

Abstract

Background Mater and Padi6 are maternal effect genes that are first expressed during oocyte growth and are required for embryonic development beyond the two-cell stage in the mouse. We have recently found that PADI6 localizes to, and is required for the formation of, abundant fibrillar Triton X-100 (Triton) insoluble structures termed the oocyte cytoplasmic lattices (CPLs). Given their similar expression profiles and mutant mouse phenotypes, we have been testing the hypothesis that MATER also plays a role in CPL formation and/or function.Methodology/FindingsHerein, we show that PADI6 and MATER co-localize throughout the oocyte cytoplasm following Triton extraction, suggesting that MATER co-localizes with PADI6 at the CPLs. Additionally, the solubility of PADI6 was dramatically increased in Matertm/tm oocytes following Triton extraction, suggesting that MATER is involved in CPL nucleation. This prediction is supported by transmission electron microscopic analysis of Mater+/+ and Matertm/tm germinal vesicle stage oocytes which illustrated that volume fraction of CPLs was reduced by 90% in Matertm/tm oocytes compared to Mater+/+ oocytes.ConclusionsTaken together, these results suggest that, similar to PADI6, MATER is also required for CPL formation. Given that PADI6 and MATER are essential for female fertility, these results not only strengthen the hypothesis that the lattices play a critical role in mediating events during the oocyte-to-embryo transition but also increase our understanding of the molecular nature of the CPLs.

Effects of ubiquitin C-terminal hydrolase L1 deficiency on mouse ova

“…This result provides further support for our previous work (Sekiguchi et al 2006). Recent reports have shown that NLRP5 also localizes to the CPLs, and Mater tm/tm mouse ova lack CPLs (Kim et al 2010, Tashiro et al 2010. Unlike Nlrp5 hypomorphic mice, gad mouse ova containing excess NLRP5 protein showed normal CPLs.…”

NLRP5 Mediates Mitochondrial Function in Mouse Oocytes and Embryos1

“…The approach to Nlrp5 disruption has been previously described [2]; since then it has been confirmed that this approach caused severe down-regulation (;90%-95%) of NLRP5 protein in the oocytes [20], and was termed Nlrp5 tm/tm (targeted mutation). Previous studies of Nlrp5 tm/tm mice indicate that the ovarian follicle pool in young mice is normal with comparable numbers of ovulated oocytes.…”

The subcortical maternal complex: multiple functions for one biological structure?

“…Additional work confirmed their involvement in ribosomal storage in oocytes [28] and showed that PADI6, NLRP5/MATER [32], and FLOPED/OOEP co-localize at the CPLs and are required for their formation. These studies unexpectedly raised the possibility of a physical association and a potential interaction between CPLs and the SCMC, which indeed share localization, pattern of expression during oocyte growth, and embryo development and null phenotype of their components.…”