• Korean Journal of Animal Reproduction
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• v.21 no.2
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• pp.157-165
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• 1997

포유류 배반포배의 epiblast는 내세포괴에 포함되어 있으며, 이 epiblast cells이 배 및 태아의 생식세포와 일반 체세포로 분화된다 (Beddington, 1986; Lawson 등, 1991). 그런데 조기에 발달된 부화배반포기 배가 지연발생된 부화배반포기 배보다도 많은 epiblast cells을 가지고 있다고 한다(Talbot 등, 1995). 그래서 본 연구에서는 체외수정 유래의 배반포배의 발육속도에 따른 내세포괴/영양배엽세포의 비율 및 배아간세포 확립 효율을 비교하여 발달일령 간에 차이가 있는지를 규명하고자 하였다. 공시한 소의 난포란을 TCM-199에 0.5$\mu\textrm{g}$/ml FSH, 5$\mu\textrm{g}$/ml LH, 10% FBS, 100 units/ml penicilin, 및 100$\mu\textrm{g}$/ml streptomycin을 첨가하여 39$^{\circ}C$, 5% CO2 조건하에서 24시간 동안 체외성숙한 후, 5$\mu\textrm{g}$/ml heparin으로 수정능이 획득된 1$\times$106 sperm/ml의 정자로 체외수정을 유도하였다. 체외수정 후 18~20시간에 과립막세포를 vortexing으로 제거하여 얻은 모든 체외수정란을 3mg/ml BSA, 20${\mu}\ell$/ml NEM amino acids, 40${\mu}\ell$/ml BME amino acids, 10mM glycine 및 1mM alanine이 함유된 CR1aa 배양액에서 BRL 단층세포와 공배양을 실시하였다. 수정후 7, 8 및 9일재 (체외수정일 : 0일)에 확장배반포기까지 발달한 수정란을 이중염색 및 배아간세포의 확립 실험에 공시하였다. 체외수정후 24시간에 분할된 총 1,145개의 수정란이 7, 8 및 9일째에 후기 배반포기까지 각각 222(15.6%), 103(7.2%) 및 52(3.6%)로 발달하여 총 377개 (26.4%)가 발달하였다. 내세포괴/영양배엽세포의 비율은 7일 및 8일째 배반포배에서 각각 47.2$\pm$11.9/95.1$\pm$24.4개 (33/67%) 및 40.3$\pm$12.4/83.3$\pm$26.9개 (33/67%)로서 9일째 배반포배의 19.3$\pm$8.1/62.3$\pm$23.1개 (24/76%) 보다 유의적(P<0.05)으로 높았다. ES-like cells을 확립하기 위하여 후기배반포기 배를 mouse embryonic fibroblast 단층 공배양기에 옮긴 후 5일에 내세포괴의 부착 여부를 판정하고, 10일에 배아간세포의 확립 여부를 판정하였다. 그 결과 7, 8 및 9일째의 배반포기배의 각각 47.7% (82/172), 30.9%(22/71) 및 15.6%(5/32)에서 배아간세포가 확립되었다. 이상의 결과에서 배반포기까지의 발육이 빠른 수정란에서 영양배엽에 대한 내세포괴세포의 비율이 높았고 배아간세포의 확립율도 높다는 사실을 입증할 수 있었으며, 이와 같은 결과에서 체외수정란 유래 배반포배의 질을 결정할 수 있을 것으로 생각된다.

• Korean Journal of Animal Reproduction
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• v.21 no.2
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• pp.167-176
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• 1997

This study was carried out to evaluate the potential for preselection of transgenic embryos prior to transfer into recipient animals. In these experiments, I used a 3.2 kb transgene which contained the neomycin resistance gene (neo) and lac Z gene driven by the $\beta$ actin promoter (iacZ Ineo). Oocytes were aspirated from abattoir ovaries, matured in TCM-199 supplemented with 10% fetal bovine serum (FBS), 5 ${\mu}\textrm{g}$/ml LH, 0.5 ${\mu}\textrm{g}$/ml FSH, 100 unit/ml penicillin, and 100 ${\mu}\textrm{g}$/ml streptomycin for 22 to 24 hrs then inseminated with a sperm suspension of 1 X 10$^6$ sperm/ml containing 5 ${\mu}\textrm{g}$/ml of heparin. At 18-20 hrs after insemination, cumulus cells were removed by vortexing and pronuclei of centrifuged zygotes microinjected with the lacZ/neo construct (3 ng/$\mu$l). All cultures were carried out in CR1aa with transfected BRL monolayers containing 3 mg/ml BSA, 20 $\mu$/ml NEM amino acids and 40 $\mu$I/ml BME amino acids. To identify the appropriate concentration of G418 for selection, non-microinjected zygotes were cultured in the presence of 0, 50, 100 and 200 $\mu$g/ml of G418. After 8 days of culture in these treatments, 44/145 (30.3%), 13/150 (8. 7%), 1/151 (0.7%) and 0/134 (0.0%) devel-oped to the blastocyst stage in 0, 50, 100 and 200 $\mu$g/ml of G418, respectively. A total of 1,127 zygotes were microinjected and placed into culture (without G418) and subsequently 710 (63.0%) cleaved. At 48 hrs post-injection, embryos ($\geq$2-cell) were randomly assigned to control (medium alone) or G418 (100 ${\mu}\textrm{g}$/ml) treatments. A control culture of 740 non-microinjected embryos from the same replicates of embryos were also placed into control medium. After 8 days in culture, 54/343 (15.7%) and 22/367 (6.0 %) of the microinjected embryos developed to the blastocyst stage in control and G418 media, respectively. A total of 151/740 (27.2%) of the non-microinjected embryos placed in the control medium developed to the blastocyst stage. The blastocysts in the control treatment had a mean of 70.7 ${\pm}$ 4.7 cells of which 23.1 ${\pm}$ 2.6 (32.7%) stained for $\beta$-Gal activity. B1astocysts in the G418 treatment had a mean of 48.8${\pm}$7.5 cells of which 40.3 ${\pm}$ 4.1 (82.6%) stained for $\beta$-Gal ac tivity (P<0.05). In the control treatment 26 of 30 (87.0%) blastocysts had some cells with $\beta$-Gal activity while all of the blastocysts in the G418 treatment had some cell with $\beta$-Gal ac tivity (P<0.05). However, ICM colonies in either control or G418 treatments were not expressed any epiblast cell except of trophetoderm celIs. The $\beta$-actin promoter/lacZ gene may not be e expression or silence expression in epiblast cells These results clearly show an enrichment of blastocysts expressing the transgene in the majority of their cells after culture in the presence of G418. The exogeneous gene was not express a and silence in ICM colonies especiallly epiblast cells except of trophectederm cells. Even though the higher rate cell number expressed of exogeneous gene in the G418 treatments, a total cell number was decrease significantly (P<0.05) of which might be also drop of the establishment of ES like-cell colonies and production of transgenic animals. However, futher studies need to determine the viability of these selected embryos and the avability of production of transgenic offspring.