CRISPRs(clustered regularly interspaced short palindromic repeats) / CRISPR - associated(CAS) system has been used genome editing technology. Genome stage modification using CRISPR/CAS9 system can be used to wide research for the gene functional study and therapeutics. However, improving of CRISPR/CAS9 system in efficiency is essential for application in various fields. Here, we treated various chemicals during the procine early embryo development to increase the mutation of target site by NHEJ(non-homologous end joining). Firstly, we confirmed the chemical toxicity after parthenogenetic activation and then check embryo puality using by counting of total cell number and TUNEL Assay in blastocyst satge. To check any improvement on mutation rate by NHEJ pathway. AZT(3′-Azido-3′-deoxythymidine, antiretroviral drug – 0.1 μM) was treated after injection of cas9 and sgRNA target to OCT4 exon 5 during the zygote stage, followed by PCR sequencing. As a result, AZT treated group shows a significantly increased in knock-out efficiency as a consequence of NHEJ. Nocodazole(anti-neoplastic agent – 200ng/ml), RO-3306 (specific inhibitor of CDK1 - 10 μM) and NU-7026(PKC signalling inhibitor - 50 μM) was treated after injection of cas9 and sgRNA with eGFP vector during the zygote stage(hpa8~hpa20) and checked a efficiency of knock-in by PCR sequencing. Interestingly, nocodazole treatment groups increased of insertion of eGFP sequence in blastocyst stage compared with non-treat group(control : 8.33%, nocodazole treatment : 16.67%). However, RO-3306 and NU-7026 made a no impact. In summary, CRISPR/CAS9 system with treatment of chemicals during porcine embryogenesis can be improving of site-specific mutation and enhancement of CRISPR genome editing.

Heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP A2/B1) have a important role in influence of pre-messenger RNA (pre-mRNA) processing and mRNA metabolism and transportation in cells. Recently, hnRNP A2/B1 can recognize m6A modifications on pre-mRNA or pre-miRNA and affect alternative splicing and miRNA processing in HeLa Cells. However, roles of hnRNP A2/B1 in various cells and tissues, especially in elary embryo development, are unclear. Here, we investigated the temporal and spatial expression patterns of hnRNPA2B13 during mammalian early embryo development. In mouse, hnRNPA2B1 was localized at the nucleus after 1-cell stage, however, hnRNPA2B1 was expressed after 2-cell stage in pig. Then, knockdown of hnRNP A2/B1 induced by RNA interference (RNAi) was used to analyze the effect of hnRNP A2/B1 in preimplantation develop in pigs. Knockdown of hnRNP A2/B1 delayed embryo development. Interestingly, ICM marker OCT4 and Sox2 was significantly decreased in blastocyst stage. mRNA expression show that transcription factors which is Pou5f1, Sox2, Nanog, Cdx2 and AP2γwas decreased the transcription levels without the changing of junction protein, ZO-1, occludin, and CXADR. Outgrowth results indicated that knock-down of hnRNPA2B1 embryos cannot format the colony. Knock-down of Methyltransferase like 3(METTL3) embryos mislocalized the hnRNPA2/B1 at the nucleus. In summary, the expression patterns of hnRNPA2/B1 differ between mouse and porcine embryos, and these differences may reflect species-specific functions during preimplantation embryo development. Our results suggested that hnRNPA2/B1 is necessary for newly synthesis of mRNA related with transcription factor, and early embryo development by the RNA epigenetic modification.

CDK2 inhibition plays a central role in DNA damage–induced cell cycle arrest and DNA repair. However, whether CDK2 also influences early porcine embryo development is unknown. In this study, we examined whether CDK2 is involved in the regulation of oocyte meiosis and early embryonic development of porcine. We found that disrupting CDK2 activity with RNAi or an inhibitor did not affect meiotic resumption or MII arrest. However, CDK2 inhibitor-treated embryos showed delayed cleavage and ceased development before the blastocyst stage. Disrupting CDK2 activity is able to induce sustained DNA damage as demonstrated by the formation of distinct γH2AX foci in nuclei of day 3- and day 5-embryos. Inhibiting CDK2 triggers a DNA damage checkpoint by activating of the ATM-P53-P21 pathway. However, the mRNA expression of genes involved in non-homologous end-joining (NHEJ) or homologous recombination (HR) pathways for double strand break (DSB) repair reduced after administering CDK2 inhibitor to 5-day-old embryos. Furthermore, CDK2 inhibition caused apoptosis in day 7 blastocysts. Thus, our results indicate that an ATM-P53-P21 DNA damage checkpoint is intact in the absence of CDK2; however, CDK2 is important for proper repair of the damaged DNA by either directly or indirectly influencing DNA repair-related gene expression.

Zinc (Zn2+) is one of essential factors during mammalian oocyte maturation and fertilization. Previous studies showed that depletion of cellular Zn by metalion chelator impair asymmetric division of oocyte. But the detailed mechanism of these phenomena is unclear. We found that depletions of zinc by cell-permeable heavy metal chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethane-1,2-diamine (TPEN) caused the decrease of cytoplasmic actin mesh level. Spire2-GFP is co-localized with zinc at the cortex and intracellular vesicle. By the treatment of TPEN, number of Spire2-GFP decorated vesicle is drastically decreased, indicating that Zn2+is essential for the localization of the spire in mouse oocyte. Two putative zinc-binding regions were located in the C-terminal part of Spire2. Mutations of zinc binding site on spire abolish its localization at the intracellular vesicle. Over expression of C-terminal region containing zinc binding site of spire impair oocyte maturations and decrease cytoplasmic actin mesh. Taken together, these results suggest that intracellular zinc is crucial for the proper localizations of spire in the mouse oocyte, and unraveling the novel regulatory mode of actin nucleator spire by Zn2+.

Mitotic spindle formation is regulated by centrosomes, composed of a centriole pair surrounded by pericentriolar materials(PCM) proteins. However, mammalian oocytes rely on acentriolar MTOCs for the function of meiotic spindle. The composition of acentriolar MTOCs and the molecular precesses that regulate the localization and accumulation in mammalian oocyte are not well understood. In this study, we analyzed the mechanisms of spindle microtubule nucleation and stability from MTOCs in mouse oocyte, and indentified Centrosomal protein192(CEP192) as a key regulator for acentriolar MTOC formation. CEP192 specifically colocalized with pericentrin (PCNT) during the oocyte maturaion. CEP192 proteins are localized throughout cytoplasm and around nucleus at GV stage, and then after BD stage, CEP192 proteins were further fragmented into smaller MTOCs around chromosomes. At metaphase, CEP192 proteins were concentrated in spindle pole. Knockdown of CEP192 using siRNAs resulted in metaphase I arrest. The arrested oocytes were characterized by reduced microtubule intensity and misalignment chromosome. Also at BD and ProMI stage, the oocytes reduced microtubule density and PCNT intensity. To confirm the mechanism of CEP192 regulation, we confirmed that PLK1 and AuroraA kinase were involved in CEP192 activation. The investigations for detailed molecular mechanisms of CEP192 and RanGTP for microtubule nucleation in oocytes are underway using various techniques including siRNA, mRNA, and positive or negative dominant injection and inhibitors.

Maturation-promoting factor (MPF) is well-known as cell cycle regulator during oocyte maturation and fertilization. MPF activity maintains high levels and arrest the cell cycle progression until fertilization. After fertilization, Anaphase-promoting complex/cyclosome (APC/C) mediated degradation of cyclin B causes decrease of MPF activity. One of the cytostatic factor (CSF), Emi2 inhibits APC/C activity by binding to APC/C-cdc20, therefore blocks the proteolysis of cyclin B. Degradation of Emi2 requires phosphorylation by Polo-like kinase 1 (Plk1). Thus recognition and phosphorylation of Emi2 by Plk1 are essential step for meiotic cell cycle resumption. In our previous research, we found that two phosphorylated threonine regions at amino acid position 152 and 176 in Emi2 are respectively contributed for recognition by polo-box domain of Plk1. Peptidomimetics 103-8 can block the interaction between Plk1-PBD and Emi2, and therefore meiotic maturation and meiosis resumption via parthenogenetic activation were impaired. However, major drawback of 103-8 was the limitation of penetration through the cell membrane. We synthesized the new peptidomimetics and checked bioavailability in mammalian oocyte by injection and media treatment. Medium treatment with peptidomimetics C-4, meiotic maturation has significantly decreased and meiotic resumption via parthenogenetic activation has perfectly impaired. For the next experiment, we are preparing X-ray crystallography to identify the binding modes between Plk1-PBD and peptidomimetics C-4.

Actin nucleation factors, which promote the formation of new actin filaments, have emerged in the last decade as key regulatory factors controlling asymmetric division in mammalian oocytes. Actin nucleators such as formin-2, spire, and the ARP2/3 complex have been found to be important regulators of actin remodeling during oocyte maturation. We found that actin nucleation promoting factor called WASP homolog-associated protein with actin, membranes and microtubules (WHAMM) play crucial roles in mouse oocyte maturation by generation of ER-associated actin filaments during meiotic spindle migrations. We also investigate regulatory mechanism of actin nucleator spire and discovered the novel roles of Zinc in regulating spire localization and cytoplasmic actin mesh formation. Another class of actin-binding proteins including cofilin, tropomyosin, capping proteins and tropomodulin, are thought to control actin cytoskeleton dynamics at various steps of oocyte maturation. The heterodimeric actin-capping protein (CP) binds to the fast-growing (barbed) ends of actin filaments and plays essential roles in various actin-mediated cellular processes. When CP is knockdowned or inhibitory component was overexpressed, asymmetric divisions of oocytes have been compromised. It turns out that knockdown or inhibition of CP deplete cytoplasmic actin mesh level, which have been known to be essential for maintain cytoplasmic actin mesh. Another actin binding proteins, tropomodulin 3 (Tmod3), binds to the slow-growing end of actin filaments and knockdown or expression deletion mutant of Tmod3 also decrease actin mesh level in maturing oocyte and it severely ablated asymmetric division of oocyte. Finally, tropomyosin 3, actin filament binding proteins protect actin filament from depolymerization, is also important to maintain cortex integrity in maturing oocyte, therefore showed the importance maintenance of actin filaments during oocyte maturation. Taken together, our study on various actin nucleator and actin binding study showed the importance of actin dynamics in mammalian oocyte maturation and early embryonic developments.

Dynamic reorganization of actin filaments is essential for various stages of mammalian oocyte maturation, including spindle migration, actin cap formation, polar body extrusion, and cytokinesis. Various actin binding proteins (ABPs) have been known to be involved in the regulation of actin filament remodeling. We elucidate roles of three different actin binding proteins in mouse oocyte maturation. The heterodimeric actin-capping protein (CP) binds to the fast-growing(barbed) ends of actin filaments and plays essential roles in various actin-mediated cellular processes. When CP is knockdowned or inhibitory component was overexpressed, asymmetric division of oocyte have been compromised. It turns out that knockdown or inhibition of CP deplete cytoplasmic actin mesh level, which have been known to be essential for maintain cytoplasmic actin mesh. Another actin binding proteins, tropomodulin 3 (Tmod3), binds to the slow-growing end of actin filaments and knockdown or expression deletion mutant of Tmod3 also decrease actin mesh level in maturing oocyte and it severely ablated asymmetric division of oocyte. Finally, tropomyosin 3, actin filament binding proteins protect actin filament from depolymerization, is also important to maintain cortex integrity in maturing oocyte. Taken together, these finding showed the essential roles of actin binding proteins in remodeling of actin filaments in mammalian oocyte development.