Potential role for MATER in cytoplasmic lattice formation in murine oocytes.
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.


RESULTS
Herein, 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 Mater(tm/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 Mater(tm/tm) germinal vesicle stage oocytes which illustrated that volume fraction of CPLs was reduced by 90% in Mater(tm/tm) oocytes compared to Mater(+/+) oocytes.


CONCLUSIONS
Taken 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.
Kim
Boram
B
Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA.
Kan
Rui
R
Anguish
Lynne
L
Nelson
Lawrence M
LM
Coonrod
Scott A
SA
D000818:Animals; D000941:Antigens / Q000235:genetics / Q000378:metabolism*; D003593:Cytoplasm / Q000737:chemistry* / Q000378:metabolism*; D004527:Egg Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D006867:Hydrolases / Q000235:genetics / Q000378:metabolism; D009865:Oocytes / Q000737:chemistry / Q000378:metabolism*; D021381:Protein Transport; D000080065:Protein-Arginine Deiminase Type 6; D000076342:Protein-Arginine Deiminases
D000941:Antigens; D004527:Egg Proteins; D006867:Hydrolases; D000080065:Protein-Arginine Deiminase Type 6; D000076342:Protein-Arginine Deiminases; C416503:Nalp5 protein, mouse; C523190:PADI6 protein, mouse