DNA methyltransferase 1 (Dnmt1) gene contains three different isoform transcripts, Dnmt1s, Dnmt1o, and Dnmt1p, are produced by alternative usage of multiple first exons. Dnmt1o is specific to oocytes and preimplantation embryos, whereas Dnmt1s is expressed in somatic cells. Here we determined that porcine Dnmt1o gene had differentially methylated regions (DMRs) in 5’-flanking region, while those were not found in the Dnmt1s promoter region. The methylation patterns of the porcine Dnmt1o/Dnmt1s DMRs were investigated using bisulfite sequencing and pyrosequencing analysis through all preimplantation stages from one cell to blastocyst stage in in vivo or somatic cell nuclear transfer (SCNT). The Dnmt1o DMRs contained 8 CpG sites, which located in —640 bp to —30 bp upstream region from transcription start site of the Dnmt1o gene. The methylation status of 5 CpGs within the Dnmt1o DMRs were distinctively different at each stage from one-cell to blastocyst stage in the in vivo or SCNT, respectively. 55.62% methylation degree of the Dnmt1o DMRs in the in vivo was increased up to 84.38% in the SCNT embryo, moreover, de novo methylation and demethylation occurred during development of porcine embryos from the one-cell stage to the blastocyst stage. However, the DNA methylation states at CpG sites in the Dnmt1s promoter regions were hypomethylated, and dramatically not changed through one-cell to blastocyst stage in the in vivo or SCNT embryos. In the present study, we demonstrated that the DMRs in the promoter region of the porcine Dnmt1o was well conserved, contributing to establishment and maintenance of genome-wide patterns of DNA methylation in early embryonic development.

The objective of this study was to examine effect of ethylene glycol for semen cryopreservation in Korean Jeju Black Bull. The semen was cryopreserved with extenders containing cryoprotectants (7% glycerol and 3%, 5%, 7% ethylene glycol) and packed to 0.5 ml straws. The semen straws were located above 3 cm of liquid nitrogen for 5 min, 5 cm for 10 min and 8 cm for 10 min. And then frozen straw was plunged into LN2. Post-thawed sperm motility, viability and membrane integrity were significantly higher in 5% ethylene glycol (72.5±5.00%, 54.88±0.66% and 46.00±2.40%; p<0.05). Motility and viability were similar between 7% glycerol and 5% ethylene glycol. However, the membrane integrity was significantly higher in 5% ethylene glycol (34.69±4.64% vs 46.00±2.40%; p<0.05). The viability and membrane integrity were significantly higher in 5 cm for 10 min and 8 cm for 10 min than 3 cm for 5 min (viability: 55.81±2.94, 55.19±3.34 vs 47.94±3.48%; p<0.05 and membrane integrity: 44.94±3.51, 46.06±2.25 vs 40.38±1.03%; p<0.05). The percentage of capacitated sperm assessed by CTC staining, percentage of F pattern was higher in 7% glycerol, 5% and 7% ethylene glycol, and AR pattern was significantly higher in 3% ethylene glycol. F pattern was significantly increased in 5 cm for 10 min and 8 cm for 10 min (p<0.05), but AR pattern was significantly increased in 3 cm for 5 min (p<0.05).

The aim of this study was to evaluate the effect of α-tocopherol on blastocysts development and subsequent cryosurvival of the vitrification. The α-tocopherol(0, 100, 200, 400 μM) was added in to culture medium for the bovine embryos. The blasocysts from the α-tocopherol and untreated control groups were then frozen-thawed, and their cryosurvival was assessed by in vitro culture for 48 h. There were no differences in the overall cleavage rate(56.14±4.66, 58.18±4.70, 62.97±6.86 and 51.17±7.28) among four treatment groups. However, in blastocyst development and total cell number were significantly higher in α-tocopherol 200 μM(38.60±7.12; 106.33±3.50) to culture medium than other treatment groups(29.30±5.24, 31.60±7.12 and 26.37±4.18; 101.36±5.12, 97.27±2.87, and 91.23±7.52 respectively). Before and after vitrification, the total cell number and blastocyst development of embryo were significantly higher in July to August than September to October. In conclusion, addition of α-tocopherol 200 μM to in vitro bovine embryo culture medium was beneficial for improving embryo quality by decreasing the embryo damage blsstocysts cell number and improving the tolerance of the embryos to cryopreservation.

The objective of this study was to investigate the relationship between estrous expression, body condition score (BCS), blood urea nitrogen (BUN) and number of transferable embryos for the purpose of improving reproductive performance in blood of Hanwoo donors. Sixty, at random stages of the estrous cycle, received a CIDR. Four days later, the animals were superovulated with a total of 28AU FSH (Antorin, 2AU=1 ml) administered twice daily in constant doses over 4 days. On the 3th administration of FSH, CIDR was withdrawn and 25 mg PGF2α was administered. Cows were artificially inseminated twice after estrous detection at 12 hr intervals. The cows received 100 μg GnRH at the time of 1nd insemination. Embryos were recovered 7 or 8 days after the 1st insemination. The estrous inducement rate and estrous expression rate were significantly lower for cows with BCS below 2.25 than for cows with BCS above 2.25. There was 50.0% of rate of mounting in cows with BCS below 2.25 whereas the rate of mounting was markedly increased in cows with BCS above 2.25 (94.1% and 89.5% for BCS 2.25～2.75 and BCS above 2.75 cows, respectively). Cows with BCS ＜2.25, 2.25～2.75 and ≥2.75 had number of transferable embryos of 4.5±0.7, 5.9±1.8 and 5.6±2.3 respectively.

The objective of this study was to investigate the relationship between concentration of urea nitrogen, glucose, cholesterol and number of transferable embryos for the purpose of improving reproductive performance in blood of Hanwoo donors. Fifty five, at random stages of the estrous cycle, received a CIDR. Four days later, the animals were superovulated with a total of 28AU FSH (Antorin, 2AU=1 ml) administered twice daily in constant doses over 4 days. On the 3th administration of FSH, CIDR was withdrawn and 25 mg PGF2α was administered. Cows were artificially inseminated twice after estrous detection at 12 hr intervals. The cows received 100μg GnRH at the time of 1nd insemination. Embryos were recovered 7 or 8 days after the 1st insemination. Cows with BUN ＜10, 11～18 and ≥19 mg/dl had number of transferable embryos of 4.3±1.3, 5.8±1.8 and 4.7±2.1 respectively. The mean numbers of total ova from < 10 and 10≤ of corpora lutea(CL) was 8.9 and 14.3, respectively. The number of transferable embryos differed between < 10 and 10≤ CL was 4.8 and 5.6, respectively.

In the present study, we identified differentially methylated region (DMR) upstream of Dnmt1o and Dnmt1s gene in early porcine embryos. Porcine Dnmt1o had at least one DMR which was located between —530 bp to —30 bp upstream from transcription start site of the Dnmt1o gene. DNA methylation analyses of Dnmt1o revealed the DMR to be hypomethylated in oocytes, whereas it was highly methylated in sperm. Moreover, the DMR upstream of Dnmt1o was gradually hypermethylated from oocytes to two cells and dramatically changed in the methylation pattern from four cells to BL stages in an in vivo. In an IVF, the methylation status in the DMR upstream of Dnmt1o was hypermethylated from one cell to eight cells, but demethylated at the Morula and BL stages, indicating that the DNA methylation pattern in the Dnmt1o upstream ultimately changed from stage to stage before the implantation. Next, to elucidate whether DNA methylation status of Dnmt1s upstream is stage-by-stage changed in during porcine early development, we analyzed the dynamics of the DNA methylation status of the Dnmt1s locus in germ cell, or one cell to BL cells. The Dnmt1s upstream was highly methylated in one and eight cells, while less methylated in two, four, morula, and BL cells. Taken together, our data demonstrated that DNA methylation and demethylation events in upstream of Dnmt1o/Dnmt1s during early porcine embryos dramatically occurred, and this change may contribute to the maintenance of genomewide DNA methylation in early embryonic development.

포유동물 수정란의 동결보존기술은 최근 기후 변화에 따른 생물종 다양성을 보존하기 위해서 중요하게 여겨지는 연구 분야이다. 따라서 멸실 위험에 처한 동물의 개량과 증식, 보존과 복원 및 생명공학의 분야에 이르기까지 응용 기술은 다양하게 이용되어진다. 본 연구에서는 한우 수정란의 동결 후 생존성 향상을 위해서 동결 방법에 따른 체내 외수정한의 내동성을 조사하였다. 완만동결에 따른 체내 외수정란의 동결 융해 후 수정란의 재확장률은 89.6%와 81.5% 그리

This study was carried out to establish most suitable freezing condition, to evaluate the different glycerol concentration of freezing and thawing rates on motility, viability, membrane integrity and acrosome intecrity of frozen Korean Jeju Black Bull spermatozoa, Semen was collected from a Korean Jeju Black Bull using an artificial vagina and transported to the laboratory. The semen was extended gradually 1:5 then cooled slowly for 2 hrs to 4. The semen was diluted 1:1 with cryoprotectant extenders (3%, 5% and 7% glycerol) and equilibrated for 2 hrs at cold chamber and packed to 0.5 ml straws. The semen straws were located above 3 cm of liquid nitrogen for 5 minutes, above 5 cm for 10 min and above 8 cm for 10 min. And then the frozen straw was plunged into LN. The presented straws were examined the viability and motility after thawed at 37 water bath. The viability and membrane integrity immediately post-thawing were significantly higher in samples frozen in 7% glycerol than 3% and 5% glycerol (p<0.05). After CTC staining to assess acrosome integrity, F pattern was significantly increased, but B pattern was significantly decreased in 7% glycerol (p<0.05). Freezing distance of 5 cm from liquid nitrogen and pre-cooling for 10 min yield better survival and membrane integrity, but not significant difference. However, AR pattern according to CTC staining was significantly decreased in 3 cm for 5 min.

Previously, we reported that the osmolarity conditions in the satellite region were affected CpG DNA methylation status while Pre-1 sequence was not affected CpG DNA methylation in pNT blastocyst stage. This study was conducted to investigate the DNA methylation status of repeat sequences in pig nuclear transfer (pNT) embryos produced under different osmolarity culture conditions. Control group of pNT embryos was cultured in PZM-3 for six days. Other two treatment groups of pNT embryos were cultured in modified PZM-3 with 138 mM NaCl or 0.05 M sucrose (mPZM-3, 320 mOsmol) for two days, and then cultured in PZM-3 (270 mOsmol) for four days. The DNA methylation status of the Pre-1 sequences in blastocysts was characterized using a bisulfite-sequencing method. Intriguingly, in the present study, we found the unique DNA methylation at several non-CpG sequences at the Pre-1 sequences in all groups. The non-CpG methylation was hypermethylated in all three groups, including in vivo group (86.90% of PZM- 3; 83.87% of NaCl; 84.82% of sucrose; 90.94% of in vivo embryos). To determine whether certain non-CpG methylated sites were preferentially methylated, we also investigated the methylation degree of CpA, CpT and CpC. Excepting in vivo group, preference of methylation was CpT>CpC>CpA in all three groups investigated. These results indicate that DNA methylation of Pre-1 sequences was hypermethylated in CpG as well as non-CpG site, regardless modification of osmolarity in a culture media.

This study was performed to identify the differentially methylated region (DMR) and to examine the mRNA expression of the imprinted H19 gene in day 35 of SCNT pig fetuses. The fetus and placenta at day 35 of gestation fetuses after natural mating (Control) or of cloned pig by somatic cell nuclear transfer (SCNT) were isolated from a uterus. To investigate the mRNA expression and methylation patterns of H19 gene, tissues from fetal liver and placenta including endometrial and extraembryonic tissues were collected. The mRNA expression was evaluated by real-time PCR and methylation pattern was analyzed by bisulfite sequencing method. Bisulfite analyses demonstrated that the differentially methylated region (DMR) was located between -1694 bp to -1338 bp upstream from translation start site of the H19 gene. H19 DMR (-1694 bp to -1338 bp) exhibits a normal mono allelic methylation pattern, and heavily methylated in sperm, but not in oocyte. In contrast to these finding, the analysis of the endometrium and/or extraembryonic tissues from SCNT embryos revealed a complex methylation pattern. The DNA methylation status of DMR Region In porcine H19 gene upstream was hypo methylated in SCNT tissues but hypermethylated in control tissues. Furthermore, the mRNA expression of H19 gene in liver, endometrium, and extraembryonic tissues was significantly higher in SCNT than those of control (p<0.05). These results suggest that the aberrant mRNA expression and the abnormal methylation pattern of imprinted H19 gene might be closely related to the inadequate fetal development of a cloned fetus, contributing to the low efficiency of genomic reprogramming.

희소 한우인 칡소의 정액 동결을 위해서 레시딘을 기본 희석제로 하는 AndroMed와 Tris-egg yolk extender를 사용하여 정자의 생존율과 활력 조사를 위해서 본 연구를 수행하였다. AndroMed 희석제를 사용하였을 때 생존율과 활력은 와 의 결과를 보였다. 그리고 Tris-egg yolk extender의 경우는 각각 와 결과를 보여 생존율에서는 Tris-egg yolk 희석제가 AndroMed 희석제를 사용하였을 때보다 유의적으로(p

The objective of this work was to determine the effect of corpus luteum (CL) grade on pregnancy rate after embryo transfer in Korean cattle and we found that CL development was linked to pregnancy rate. The in vivo derived blastocyst-stage embryos were transferred to 15 recipients synchronized in the estrus cycles. Based on size and palpable characteristics, CLs were categorized into three grade. The grade three CL is not to be identified by rectal palpation. The pregnancy rates tended to increase with the increase in CL size of recipients. In grade one, two, and three, the pregnancy rates were 62.5%, 50.0%, and 0%, respectively. This result suggests that pregnancy rates after embryo transfer might be affected by the CL status of recipients.