• Korean Journal of Animal Reproduction
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• v.26 no.4
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• pp.353-360
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• 2002

Although successful pronuclear formation and apposition were seen in porcine oocytes following mouse sperm injection, little is known on the morphology of male and female pronuclei following sperm injection. The objective of this study is to describe the ultrastructure of porcine zygote following murine sperm injection in relation to the chronology of pronuclear S phase. At 40h ~ 44h following in vitro maturation, Cumulus cells were removed in TCM-HEPES with 0.1% hyaluronidase. Then, spermatozoa was injected into the cytoplasm of oocytes. After. injection, all oocytes were transferred to NCSU23 medium and cultured at 39$^{\circ}C$ under 5% $CO_2$ in air. Oocytes were fixed in 2% glutaraldehyde in Dulbeccos phosphate-buffered saline and observed by Transmission Electron Microscopy. Nuclear precursor bodies were observed in each pronucleus. A cluster of large and small granules was attached in the nucleolus precursor body. After the apposition of male and female chromatin, chromatin condensation was observed throughout the nucleoplasm and nucleolus precursor bodies and condensed chromatin in contact with clusters of small and large granules and the nuclear envelope were found in apposed pronuclear regions. These results suggest that non-species specific nuclear cytoplasmic interactions take place during pronuclear formation and apposition following sperm injection.

• Korean Journal of Animal Reproduction
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• v.26 no.4
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• pp.361-368
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• 2002

The onset of pronucleus formation and DNA synthesis in porcine oocytes following the injection of porcine or murine sperm was determined in order to obtain insights into species-specific paternal factors that contribute to fertilization. After 44h in vitro maturation, spermatozoa was injected into the cytoplasm of oocytes. After injection, all oocytes were transferred to NCSU23 medium and cultured at 39'E under 5% CO2 in air. Similar frequencies of oocytes with female pronuclei were observed after injection with porcine sperm or with murine sperm. In contrast, male pronuclei formed 8 to 9 h following the injection of porcine sperm, and 6 to 8 h following the injection of murine sperm. After pronucleus formation maternally derived microtubules were assembled and appeared to move both male and female pronuclei to the oocyte center. A few porcine oocytes entered metaphase 22 h after the injection of murine sperm, but normal cell division was not observed. The mean time of onset of S-phase in male pronuclei was 9.7 h following porcine sperm injection and 7.4 h following mouse sperm injection. These results suggested that DNA synthesis was delayed in both pronuclei until the sperm chromatin fully decondensed, and the sperm nuclear decondensing activity and microtubule nucleation abilities of the male centrosome are cell cycle dependent.

• Reproductive and Developmental Biology
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• v.32 no.4
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• pp.255-261
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• 2008

The early diagnosis of bovine pregnancy is an essential component of successful reproductive planning on farms, because lack of bovine pregnancy over the long term results in reproductive failure and low milk yield-the latter of which is a special concern on dairy farms. This study was designed to identify early pregnancy-specific whey proteins in bovine, by comparing milk samples collected from cattle during pregnancy (Days 30 and 50) and from non-pregnant cattle. In this study, differentially expressed proteins in five pregnant and five non-pregnant Holstein dairy cattle were investigated and compared, using proteomics analysis. The first dimension was applied to a pH $3.0{\sim}10.0$ strip, by loading a 2-mg milk protein sample. After the second-dimension separation was performed, the gels were stained with colloidal Coomassie brilliant blue. The stained gels were scanned and the images were analyzed, to detect variations in protein spots between non-pregnant and pregnant cattle milk protein spots, using ImageMaster, this was followed by analysis with MALDI TOF-MS. Analysis of the 2-DE gel image resulted in a total of approximately $500{\sim}600$ protein spots, of which 12 spots were differentially expressed, six spots were up-regulated, and four spots were down-regulated; two spots were identified as pregnancy-specific proteins. These proteins were identified as lactoferrin, NA-DH dehydrogenase subunit 2, albumin, serum albumin precursor and transferrin. Our results via 2-D PAGE analysis revealed composite profiles of several milk proteins related to early bovine pregnancy, implying the possible use of these milk proteins in the early detection of bovine pregnancy.

• Proceedings of the KSAR Conference
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• 2002.06a
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• pp.87-87
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• 2002

Previously, we observed high level expression of goat β-casein/genomic hGH fusion gene in mammary gland of transgenic mice. To develop an expression vector to make a human granulocyte-colony stimulating factor (hG-CSF) protein efficiently produced in milk of transgenic animals, we designed a new bicistronic vector using the goat β-casein/genomic hGH fusion gene as regulation sequences for expression and internal ribosome entry site (IRES) as a mediator for second gene expression. This vector was constructed by insertion of encephalomyocarditis virus (EMCV) IRES-dependent second gene region coupled with hG-CSF cDNA into 3' untranslated region of an intact hGH gene. By microinjcetion, four transgenic mice were generated and three of them transmitted the bicistronic vector to their progeny. (omitted)

• Reproductive and Developmental Biology
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• v.38 no.1
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• pp.41-52
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• 2014

Embryonic genome activation (EGA) is a highly complex phenomenon that is controlled at various levels. New studies have ascertained some molecular mechanisms that control EGA in several species; it is apparent that these same mechanisms regulate EGA in all species. Protein phosphorylation, DNA methylation and histone modification regulate transcriptional activities, and mechanisms such as ubiquitination, SUMOylation and microRNAs post-transcriptionally regulate development. Each of these regulations is highly dynamic in the early embryo. A better understanding of these regulatory strategies can provide the possibility to improve the reproductive properties in mammals such as pigs, to develop methods of generating high-quality embryos in vitro, and to find markers for selecting developmentally competent embryos.

• Reproductive and Developmental Biology
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• v.39 no.2
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• pp.29-36
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• 2015

Pigs are considered an ideal source of human disease model due to their physiological similarities to humans. However, the low efficiency of in vitro embryo production (IVP) is still a major barrier in the production of pig offspring with gene manipulation. Despite ongoing advances in the associated technologies, the developmental capacity of IVP pig embryos is still lower than that of their in vivo counterparts, as well as IVP embryos of other species (e.g., cattle and mice). The efficiency of IVP can be influenced by many factors that affect various critical steps in the process. The previous relevant reviews have focused on the in vitro maturation system, in vitro culture conditions, in vitro fertilization medium, issues with polyspermy, the utilized technologies, etc. In this review, we concentrate on factors that have not been fully detailed in prior reviews, such as the oocyte morphology, oocyte recovery methods, denuding procedures, first polar body morphology and embryo quality.

• Korean Journal of Animal Reproduction
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• v.26 no.4
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• pp.321-328
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• 2002

The hormone resistin is associated with type II diabetes mellitus in rodent model. Resistin impairs glucose tolerance and insulin action. A new class of anti-diabetic drugs were called thiazolidinediones (TZDs) downreguates a resistin. Resistin gene expression is induced during adipocyte differentiation and resistin polypeptide is secreted by adipocytes. But, the correlation between increased adiposity and resistin remains unknown. The objectives of this study was to clone a mouse resistin CDNA and to generate transgenic mice overexpressing mouse resistin gene. The pCMV-mus/resistin gene was prepared from previous recombinant pTargeT$^{TM}$-mus/resistin by digestion of Bgl II, and has used for microin- jection into pronuclei of one cell embryos. Mouse resistin expression was detected in transgenic F$_1$mice by RT-PCR. The transgenic mouse with resistin gene expression has heavier body weight which was measured higher level of plasma glucose than that of normal mouse. And in diet-induced experiments, in fasting group, resistin expression was higher than that of re-feeding group. This result demonstrates that the resistin gene overexpressing mice may be became to obesity and be useful as an animal disease model to be diabetes caused by insulin resistance of resistin.n.

• Korean Journal of Agricultural Science
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• v.44 no.3
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• pp.309-317
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• 2017

Melatonin (N-acetyl-5-methoxytryptamine) is an indole synthesized from tryptophan by the pineal gland in animal. The major function of melatonin is to modulate circadian and circannual rhythms in photoperiodic mammals. Importantly, however, melatonin is also a free radical scavenger, anti-oxidant, and anti-apoptotic agent. Recently, the beneficial effects of melatonin on oocyte maturation and embryonic development in vitro have been reported in many species such as pig, cattle, sheep, mouse, and human. In this review, we will discuss recent studies about the role of melatonin in the production of porcine and bovine oocytes and embryos in vitro in order to provide useful information of melatonin in oocyte maturation and embryo culture in vitro.

• Reproductive and Developmental Biology
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• v.34 no.3
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• pp.207-211
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• 2010

Current developments in IVF and animal cloning have resulted in increasing demand for large quantities of oocytes and ovarian follicles at specific stages of development. These medical and scientific needs may be met by developing an optimal culture system for preantral follicles. In this study, we investigated the growth of porcine preantral follicle cultures in different media and in the presence and absence of serum. Follicles were manually dissected from ovaries obtained from prepubertal gilts at a local slaughterhouse, and cultured for 3 days in M199 or NCSU23 medium supplemented with porcine FSH, transferrin, L-ascorbic acid and insulin. Follicle diameters were measured on day 1 and 3 of culture. In Experiment 1, the effect of supplementing culture medium with fetal calf serum (FCS) on porcine preantral follicle growth was examined. In the group of cultures supplemented with FCS, follicle diameter after 3 days of culture, survival rate and antrum formation rate in the FCS group were significantly higher than those of the control group. In Experiment 2, the effects of culture medium (M199 and NCSU23) on follicle growth were compared. Follicle diameters were increased in the M199 group, compared with those in NCSU23 (p<0.05), but we observed no significant differences in survival and antrum formation rates between cultures grown in the two media. In conclusion, supplementation of the culture medium with serum enhances preantral follicle growth and antrum formation, and M199 is superior to NUSU23 for porcine preantral follicle culture in vitro.

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.3
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• pp.148-156
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• 2019

The Transgenic livestock can be useful for the production of disease-resistant animals, pigs for xenotranplantation, animal bioreactor for therapeutic recombinant proteins and disease model animals. Previously, conventional methods without using artificial nuclease-dependent DNA cleavage system were used to produce such transgenic livestock, but their efficiency is known to be low. In the last decade, the development of artificial nucleases such as zinc-finger necleases (ZFNs), transcription activator-like effector nucleases (TALENs) and clustered regulatory interspaced short palindromic repeat (CRISPR)/Cas has led to more efficient production of knock-out and knock-in transgenic livestock. However, production of knock-in livestock is poor. In mouse, genetically modified mice are produced by coinjecting a pair of knock-in vector, which is a donor DNA, with a artificial nuclease in a pronuclear fertilized egg, but not in livestock. Gene targeting efficiency has been increased with the use of artificial nucleases, but the knock-in efficiency is still low in livestock. In many research now, somatic cell nuclear transfer (SCNT) methods used after selection of cell transfected with artificial nuclease for production of transgenic livestock. In particular, it is necessary to develop a system capable of producing transgenic livestock more efficiently by co-injection of artificial nuclease and knock-in vectors into fertilized eggs.