title: P-TEFb Kinase Activity Is Essential for Global Transcription, Resumption of Meiosis and Embryonic Genome Activation in Pig.
abstract: Positive transcription elongation factor b (P-TEFb) is a RNA polymerase II carboxyl-terminal domain (Pol II CTD) kinase that phosphorylates Ser2 of the CTD and promotes the elongation phase of transcription. Despite the fact that P-TEFb has role in many cellular processes, the role of this kinase complex remains to be understood in mammalian early developmental events. In this study, using immunocytochemical analyses, we found that the P-TEFb components, CDK9, Cyclin T1 and Cyclin T2 were localized to nuclear speckles, as well as in nucleolar-like bodies in pig germinal vesicle oocytes. Using nascent RNA labeling and small molecule inhibitors, we showed that inhibition of CDK9 activity abolished the transcription of GV oocytes globally. Moreover, using fluorescence in situ hybridization, in absence of CDK9 kinase activity the production of ribosomal RNAs was impaired. We also presented the evidences indicating that P-TEFb kinase activity is essential for resumption of oocyte meiosis and embryo development. Treatment with CDK9 inhibitors resulted in germinal vesicle arrest in maturing oocytes in vitro. Inhibition of CDK9 kinase activity did not interfere with in vitro fertilization and pronuclear formation. However, when in vitro produced zygotes were treated with CDK9 inhibitors, their development beyond the 4-cell stage was impaired. In these embryos, inhibition of CDK9 abrogated global transcriptional activity and rRNA production. Collectively, our data suggested that P-TEFb kinase activity is crucial for oocyte maturation, embryo development and regulation of RNA transcription in pig.
authors.affiliation: Department of Animal Science & Biotechnology, Research Center for Transgenic Cloned Pigs, Chungnam National University, Daejeon, 305-764, Republic of Korea.
authors.forename: Reza K
authors.initials: RK
authors.lastname: Oqani
authors.affiliation: Department of Animal Science & Biotechnology, Research Center for Transgenic Cloned Pigs, Chungnam National University, Daejeon, 305-764, Republic of Korea.
authors.forename: Tao
authors.initials: T
authors.lastname: Lin
authors.affiliation: Department of Animal Science & Biotechnology, Research Center for Transgenic Cloned Pigs, Chungnam National University, Daejeon, 305-764, Republic of Korea.
authors.forename: Jae Eun
authors.initials: JE
authors.lastname: Lee
authors.affiliation: Optipharm Inc, Cheongju, Chungbuk, 361-954, Republic of Korea.
authors.forename: Ki Myung
authors.initials: KM
authors.lastname: Choi
authors.affiliation: Department of Animal Science & Biotechnology, Research Center for Transgenic Cloned Pigs, Chungnam National University, Daejeon, 305-764, Republic of Korea.
authors.forename: Hyun Young
authors.initials: HY
authors.lastname: Shin
authors.affiliation: Department of Animal Science & Biotechnology, Research Center for Transgenic Cloned Pigs, Chungnam National University, Daejeon, 305-764, Republic of Korea.
authors.forename: Dong Il
authors.initials: DI
authors.lastname: Jin
mesh_terms: D000818:Animals; D056906:Cyclin T / Q000235:genetics; D042863:Cyclin-Dependent Kinase 9 / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics*; D004622:Embryo, Mammalian; D047108:Embryonic Development; D005260:Female; D005307:Fertilization in Vitro; D016678:Genome; D059471:In Vitro Oocyte Maturation Techniques; D008540:Meiosis / Q000235:genetics; D009865:Oocytes / Q000254:growth & development / Q000378:metabolism*; D042925:Positive Transcriptional Elongation Factor B / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics*; D013552:Swine; D014158:Transcription, Genetic
chemical_list: D056906:Cyclin T; D042925:Positive Transcriptional Elongation Factor B; D042863:Cyclin-Dependent Kinase 9