P-TEFb Kinase Activity Is Essential for Global Transcription, Resumption of Meiosis and Embryonic Genome Activation in Pig

• Published in: PloS one Vol. 11; no. 3; p. e0152254
• Main Authors: Oqani, Reza K, Lin, Tao, Lee, Jae Eun, Choi, Ki Myung, Shin, Hyun Young, Jin, Dong Il
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 24.03.2016; Public Library of Science (PLoS)
• Subjects: Animal sciences; Animals; Biology and Life Sciences; Biotechnology; Cell cycle; Cloning; Cyclin T - genetics; Cyclin T1; Cyclin-dependent kinase 9; Cyclin-Dependent Kinase 9 - antagonists & inhibitors; Cyclin-Dependent Kinase 9 - biosynthesis; Cyclin-Dependent Kinase 9 - genetics; Developmental stages; DNA-directed RNA polymerase; Elongation; Embryo, Mammalian; Embryonic Development; Embryos; Enzymes; Epigenetics; Female; Fertilization; Fertilization in Vitro; Fluorescence; Fluorescence in situ hybridization; Gene expression; Gene regulation; Genetic aspects; Genome; Genomes; Hogs; In vitro fertilization; In Vitro Oocyte Maturation Techniques; Inhibition; Inhibitors; Kinases; Meiosis; Meiosis - genetics; Nucleoli; Oocytes; Oocytes - growth & development; Oocytes - metabolism; Phosphorylation; Physiological aspects; Positive Transcriptional Elongation Factor B - antagonists & inhibitors; Positive Transcriptional Elongation Factor B - biosynthesis; Positive Transcriptional Elongation Factor B - genetics; Protein kinases; Protein synthesis; Proteins; Research and analysis methods; Ribonucleic acid; Ribosomal DNA; RNA; RNA polymerase II; rRNA; Stem cells; Studies; Swine; Transcription (Genetics); Transcription activation; Transcription elongation factor b; Transcription factors; Transcription, Genetic; Zoology; Zygotes; South Korea
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0152254

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.