This study aimed at investigating whether a porcine follicular fluid (pFF) supplementation positively affects the characteristics of donor cells and the developmental competence of porcine cloned embryos. Ear fibroblast cells (donor cell) from an Massachusetts General Hospital miniature pig were cultured in different culture methods: (1) Dulbecco's modified Eagle's medium (DMEM)+10% FBS (Control); (2) DMEM+0.5% FBS (SS); and (3) DMEM+10% FBS+10% pFF (pFF) for 72 h. In each conditioned medium, the concentrations of 4 amino acids (Thr, Glu, Pro, and Val) in the pFF group were significantly different from those in the control group (p<0.05 or p<0.01). The proliferation of the cells cultured in the SS group was significantly lower than that of the other treatment groups (p<0.01). The population of apoptotic and necrotic cells in the SS group was significantly higher than that of either the control or the pFF group (p<0.01). The number of embryos that cleaved (p<0.05) and developed into blastocysts (p<0.01) in the SS group was significantly lower than that of either the control or the pFF group. Compared to other groups, the blastocysts produced from the donor cells in the pFF group had higher total cells and lower apoptotic cells (p<0.05). It can be concluded that pFF supplementation in the donor cell culture medium positively affects cell death, cell cycle and quality of the cloned blastocyst.

Phosphoprotein Enriched in Astrocytes (PEA15) is a 15kD-sized intracellular signaling protein, highly expressed in astrocytes and constitutively expressed in peripheral tissues. Recently it was found that PEA15 expression was elevated in patients suffering type 2 diabetes and suggested to be involved in the syndrome of insulin resistance. To investigate the functional role of PEA15 for the control of blood glucose level, we produced a transgenic pig over-expressing mouse PEA15 (mPEA15). As a model animal, pig has many advantages. They have a higher fecundity and a short generation time and are physiologically similar to human. Using the transgenic pig, we carried out a series of experiments to establish a link between PEA15 expression and the insulin resistance. Our results suggested that, compared with control pig, mPEA15 pig has, (1) a higher blood resistin level, (2) a lower cell membrane-embeded GLUT4 level, and (3) a lower glucose clearing ability based on oral glucose tolerance test (OGTT). When our results combined, it can be concluded that mPEA15 over-expressing pig has many symptoms of insulin resistance and these pigs will become a useful disease model to investigate diabetes mellitus in the near future.

The overexpression of Phosphoprotein Enriched in Astrocytes (PEA15) gene is commonly found in human diabetic patients. The overexpression of this gene in skeletal muscle and fat tissues have been reported to cause insulin resistance, thereby impairing insulin stimulated glucose uptake. We introduced a gene of mouse PEA15 (mPEA15) and enhanced green fluorescent protein (EGFP) into fertilized one cell pig zygotes using microinjection, and produced a piglet that showed overexpression of mPEA15 in the muscle tissues and expression of EGFP in the ear tissues and hooves. RT-PCR RFLP, southern blot and FISH analysis showed that the tissues carried the transgene. Real-time RT-PCR and western blots demonstrated that PEA15 gene was overexpressed in the various tissues and muscle tissues, respectively. These facts suggest that expression vector system is normally expressed in the trnasgenic (TG) pigs. To use as animal diseases model for type 2 diabetes, further study is necessary to confirm whether diabetes occur in these TG pigs, especially insulin resistance.

This study was carried out between 2008 and 2009 in four dairy farms to investigate the effect of feeding of whole crop barley silage on the reproductive performance of Holstein heifers. Two diets, mixed hay or whole crop barley silage separately from concentrate were fed 6-month old Holstein heifers (=37). In control group (=CON), heifers (n=16) were fed 6 kg (/head) mixed hay and 4 kg (/head) commercial diet. In whole crop barley silage group (=WBS), heifers (n=21) were fed 10 kg (/head) whole crop barley silage, 4 kg (/head) mixed hay and 2 kg (/head) commercial diet. To manage body weight gain, the body condition score of heifers were measured every month. The results obtained were as follows: 1. Body weight in CON and WBS heifers at 13-, 14-, 15- and 17-month old were 340±17.9 and 342±13.6 kg, 356±15.7 and 366±14.7 kg, 382±13.1 and 387±14.4 kg, and 429±15.0 and 417±10.3 kg, respectively. 2. Body condition score in CON and WBS heifers at 9-, 12-, 15- and 17-month old were 2.88±0.04 and 2.80±0.04, 2.88±0.04 and 2.80±0.04, 2.89±0.08 and 3.00±0.07, and 2.89±0.08 and 3.00±0.07, respectively. 3. Average age of sexual maturity in CON and WBS heifers were 437.3±9.9days and 939.6±12.5days, WBS group heifers were significantly shorter (p<0.05) than CON group heifers. 4. First-service conception rates in CON or WBS group were 81.3% (13/16) and 66.7% (14/21), respectively, and cumulative conception rate to 2nd artificial insemination were 87.5% for CON and 85.7% for WBS group. Conception rate was not different between treatments

형질 전환 동물 생산에는 조직 및 시기 특이적 발현 조절이 가능하다는 장점 때문에 유즙 내로 외부 유전자를 발현시키는 시스템이 널리 이용되고 있다. 유전자 발현 즉, 단백질 생산은 프로모터의 강도뿐만 아니라 mRNA의 안정성에 의해서도 조절된다. 특히, polyadenylation에 의한 poly A의 길이는 in vivo와 올 in vitro에서 mRNA 안정성 및 목적 유전자의 번역효율에 영향을 준다. 본 연구에서는 이러한 mRNA 안정성이 목적 유전자의 발현에 미치는 영향을 알아보기 위해 3'-UTR 염기 서열을 분석하였다. 이 3'-untranslated region(UTR) 내의 poly A signal을 기준으로 putative cytoplasmic polyadenylation element(CPE) 부위와 downstream elements(DSE: U-rich, G-rich, GU-rich)의 염기 서열을 분석하고, 각각의 element를 기준으로 15 종의 luciferase reporter vector를 제작하여, 생쥐 유선 세포주(HC11)와 돼지 유선 세포주(PMGC)에 각각 transfection시킨 후 48시간 동안 배양하고 luciferase 발현량을 분석하였다. PMGC의 경우, luciferase의 발현은 exon 9의 CPE 2,3 및 DSE 1을 포함한 #6 construct에서 유의적으로 높은 발현량을 보였으며, exon 9의 CPE 2, 3과 DSE를 모두 포함하고 있는 #11 construct에서도 유의적으로 높은 발현량을 보였다. 이러한 결과는 형질 전환 돼지 생산에 있어 #6 및 11 construct의 사용은 목적의 유전자를 효과적으로 발현시키는데 기여할 것으로 사료된다.

Our previous study showed that transgenic (TG) pigs harboring human EPO (hEPO) gene have been shown to have reproductive disorders, including low pregnancy rates, irregular estrus cycle and low little size. To investigate these reasons, we assessed estrus behavior (standing response) and plasma 17B-estradiol (E2) level, which partly reflect reproductive function, during the estrus cycles after synchronization and superovulation by hormone treatments. Then, we analysed blood composition and expression of hEPO gene in TG pigs. Pigs were injected with PG600. After 10 days, pigs were fed with Regumate porcine for 6 days. Blood samples were collected from jugular vein. Analysis of blood composition and E2 level were measured by Hemavet 950 and E2 ELISA kit, respectively. And, the expression of hEPO gene in reproductive organs was quantitated by real-time RT-PCR. The percentage of estrus behavior in TG was significantly decreased. Hematocrit (HCT), hemoglobin (Hb) concentration and red blood cell (RBC) number were significantly higher in TG than wild type (WT). On the other hand, high expression of hEPO gene in TG was observed in the mammary gland as well as in the uterus. Moreover, plasma E2 level was significantly higher in TG than WT. These results suggest that nonspecific expression of hEPO gene in the other organs of TG may affect blood composition and plasma E2 level, thereby causing reproductive disorders.

본 연구는 돼지 골수에서 존재하는 조혈 줄기 세포 및 전구 세포를 이용해 이종 동물 모델인 태아 마우스 복강 생체 이식을 통하여 돼지 조혈 세포의 이종 조혈 조직에서의 증식과 분화 특성을 규명하였다. 선천성 면역 부전 마우스인 NOD/SCID 마우스 태아 조혈 환경에 돼지 골수 유래 조혈 줄기 세포 및 전구 세포를 이식하고, 이식 후 5주령에 마우스 조혈기관에서의 돼지 조혈 세포의 증식과 분화 특성을 돼지 특이적 항체 면역 염색으로 유세포 분석을 실시한 결과, 마우스 조혈 조직인 골수, 흉선, 간장, 비장 및 림파절에서 돼지 조혈 세포의 분화 및 증식이 관찰되었다. 특히 돼지의 T 면역세포가 골수계 세포에 비해서 높은 chimerism이 관찰되어 태생 초기의 NOD/SCID 조혈 환경에 의한 특이적 T 면역세포의 증식에 적합한 조혈 환경을 제공하고 있다는 사실이 밝혀졌다. 본 마우스 신생 NOSD/SCID 복강 이식 동물 모델을 이용해 돼지 T 면역세포의 분화 발달 연구 및 이종 장기 이식 기전 연구에 좋은 모델로서 활용이 기대된다.

During early embryo development, Oct-4 is an important transcription factor for the early differentiation. The present study was first examined methylation status in distal enhancer and promoter region of Oct-4 during mouse pre-implantation embryo development. In oocyte and sperm, high methylation was observed in both distal and proximal of promoter in Oct-4. Following fertilization, relatively high methylation level remained until 8-cell stage embryos, but decreased at the morula and blastocyst stage. Specific gene knock down of Oct-4 by siRNA injection into zygote induced higher methylation rates of both distal and proximal region ofpromoter of Oct-4. These results suggest a functional link between the DNA methylation status of distal and promoter region in the Oct-4 gene and the gene sequence-specific transcriptional silencing by exogenous siRNA injection during mouse pre- implantation embryos.

NOD/SCID 마우스는 선천성 면역결핍을 지닌 마우스로서 이종 세포 및 조직 이식을 위한 실험동물로서 가장 많이 활용되고 있다. 본 연구는 돼지의 골수조직에서 채취한 조혈줄기세포를 면역결핍마우스의 정맥 주입을 통하여 생체 내 주입을 실시한 결과, 마우스의 조혈조직에서 대단히 높은 돼지 T 면역세포의 증식이 관찰되었다. 유세포 분석기를 이용해 돼지 골수 조혈세포 생체 이식 6주의 마우스에서의 돼지 T 면역세포의 증식과 분화 특성을 분석한 결과, 마우스 조혈조직인 골수(5.4±1.9%), 비장(15.4±7.3%), 간(21.3±1.4%), 림프절(33.5±32.8%)에서 돼지 조혈줄기세포 유래 T 세포의 증식과 분화가 관찰되었고, 돼지 helper T 세포와 cytotoxic T 세포의 발달도 확인되었다. 또한 조직 면역염색을 통하여 마우스의 비장조직에 이식한 돼지 면역세포의 증식을 관찰하였다. 본 연구는 NOD/SCID 마우스를 이용해 돼지 조혈줄기세포로부터 T 면역세포로의 분화 및 발달과정을 생체 내에서 분석할 수 있는 유용한 동물모델로서 이용할 수 있음을 보여준다.