The mechanisms governing the transition from a terminally differentiated oocyte to a totipotent zygote remain poorly understood. During the previous funding period, we cloned and characterized a highly-abundant oocyte and embryo-restricted gene, peptidylarginine deiminase 6 (PADI6), from the murine egg proteome and found that it represents a novel member of an enzyme family (PADI) that converts protein arginine residues to citrulline. Our ongoing analysis of the PADI6 -/- phenotype indicates that PADI6 -/- females are infertile due to an arrest in embryogenesis at the two-cell stage, thus demonstrating that PADI6 represents a novel maternal effect gene. At the ultrastructural level, PADI6 localizes to an egg and embryo-restricted structure, the cytoskeletal sheets (CSS), that occupies over 15% of the cytoplasm in many mammals. While the function of this cytokeratin-containing structure is unknown, the CSS form during oocyte growth and undergo dramatic reorganizations at critical developmental time points;suggestive of a role in embryonic reprogramming. Strikingly, preliminary ultrastructural analysis reveals a complete dispersal of the cytoskeletal sheets in PADI6 -/- oocytes and eggs while most other structures appear normal. We also found that transcriptional activity in PADI6 -/- two-cell embryos is severely compromised, suggesting that the PADI6 defect arises due to failure to activate embryonic transcription. Based on our preliminary findings, we hypothesize that, in the oocyte, PADI6 interacts with cytokeratin via its N-terminal domain leading to nucleation of the dispersed CSS components. Following fertilization, we hypothesize that PADI6 becomes activated (most likely by calcium signaling) and citrullinates cytokeratin via its C-terminus, leading to CSS reorganization and a stage-dependent release of associated proteins which are required for embryonic genome activation (EGA).
The specific aims of this application are to: 1) Test the hypothesis that PADI6 is required for nucleation of CSS components into the mature 60 nm complex in the oocyte. 2) Test the hypothesis that PADI6 plays a role in cytoplasmic-to-nuclear signaling events in the early embryo prior to genome activation. 3) Test the hypothesis that citrullination of cytoskeletal sheet proteins by PADI6 is required for CSS anastomoses and for early development.

National Institute of Health (NIH)
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Research Project (R01)
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Cellular, Molecular and Integrative Reproduction Study Section (CMIR)
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Ravindranath, Neelakanta
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Cornell University
Schools of Veterinary Medicine
United States
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Kim, Boram; Zhang, Xuesen; Kan, Rui et al. (2014) The role of MATER in endoplasmic reticulum distribution and calcium homeostasis in mouse oocytes. Dev Biol 386:331-9
Anguish, Lynne; Coonrod, Scott (2013) Preparation of mammalian oocytes for transmission electron microscopy. Methods Mol Biol 957:213-30
Kan, Rui; Yurttas, Piraye; Kim, Boram et al. (2011) Regulation of mouse oocyte microtubule and organelle dynamics by PADI6 and the cytoplasmic lattices. Dev Biol 350:311-22
Morency, Eric; Anguish, Lynne; Coonrod, Scott (2011) Subcellular localization of cytoplasmic lattice-associated proteins is dependent upon fixation and processing procedures. PLoS One 6:e17226
Yurttas, Piraye; Morency, Eric; Coonrod, Scott A (2010) Use of proteomics to identify highly abundant maternal factors that drive the egg-to-embryo transition. Reproduction 139:809-23
Kim, Boram; Kan, Rui; Anguish, Lynne et al. (2010) Potential role for MATER in cytoplasmic lattice formation in murine oocytes. PLoS One 5:e12587
Borillo, Jason; Coonrod, Scott A; Wu, Jean et al. (2008) Antibodies to two ZP3 B cell epitopes affect zona pellucida assembly. J Reprod Immunol 78:149-57
Yurttas, Piraye; Vitale, Alejandra M; Fitzhenry, Robert J et al. (2008) Role for PADI6 and the cytoplasmic lattices in ribosomal storage in oocytes and translational control in the early mouse embryo. Development 135:2627-36
Coonrod, Scott; Vitale, Alejandra; Duan, Chongwen et al. (2006) Testis-specific lactate dehydrogenase (LDH-C4; Ldh3) in murine oocytes and preimplantation embryos. J Androl 27:502-9
Vitale, Alejandra; Perlin, Julie; Leonelli, Lauriebeth et al. (2005) Mouse cPLA2gamma, a novel oocyte and early embryo-abundant phospholipase A2 gamma-like protein, is targeted to the nuclear envelope during germinal vesicle breakdown. Dev Biol 282:374-84

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