title: Nucleolar Translocation of Histone Deacetylase 2 Is Involved in Regulation of Transcriptional Silencing in the Cat Germinal Vesicle.
abstract: Histone deacetylase 2 (HDAC2) is a key transcriptional coregulator that is suspected to play a role during oogenesis. It is known that RNA transcription in the cat germinal vesicle (GV) stops during folliculogenesis at the late antral follicle stage and is unrelated to histone deacetylation or chromatin condensation. The objective of the present study was to determine if and how HDAC2 participates in transcription regulation in the cat GV. Spatiotemporal HDAC2 protein expression was examined by immunostaining oocytes from primary to large antral follicles. HDAC2 was detected in the majority of GVs within oocytes from early, small, and large antral follicles. At early and small antral stages, HDAC2 was found primarily in the GV's nucleoplasm. There then was a significant shift in HDAC2 localization into the nucleolus, mostly in oocytes from large antral follicles. Assessments revealed that transcription was active in oocytes that contained nucleoplasm-localized HDAC2, whereas nucleolar-bound HDAC2 was associated with loss of both global transcription and ribosomal RNA presence at all antral stages. When oocytes were exposed to the HDAC inhibitor valproic acid, results indicated that HDAC regulated transcriptional activity in the nucleoplasm, but not in the nucleolus. Collective results suggest that nucleolar translocation of HDAC2 is associated with transcriptional silencing in the GV, thereby likely contributing to an oocyte's acquisition of competence.
authors.affiliation: Center for Species Survival, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, District of Columbia, and Front Royal, Virginia.
authors.forename: Pei-Chih
authors.initials: PC
authors.lastname: Lee
authors.affiliation: Center for Species Survival, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, District of Columbia, and Front Royal, Virginia.
authors.forename: David E
authors.initials: DE
authors.lastname: Wildt
authors.affiliation: Center for Species Survival, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, District of Columbia, and Front Royal, Virginia comizzolip@si.edu.
authors.forename: Pierre
authors.initials: P
authors.lastname: Comizzoli
mesh_terms: D000818:Animals; D002415:Cats; D002466:Cell Nucleolus / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism; D005260:Female; D018858:Germinal Center / Q000378:metabolism*; D056464:Histone Deacetylase 2 / Q000235:genetics / Q000378:metabolism*; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology; D009865:Oocytes / Q000378:metabolism; D009866:Oogenesis / Q000235:genetics; D006080:Ovarian Follicle / Q000378:metabolism; D011247:Pregnancy; D012313:RNA / Q000096:biosynthesis / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics; D014635:Valproic Acid / Q000494:pharmacology
chemical_list: D002843:Chromatin; D056572:Histone Deacetylase Inhibitors; D014635:Valproic Acid; D012313:RNA; D056464:Histone Deacetylase 2
keywords: domestic cat; gamete biology; germinal vesicle; oocyte; transcription