DNA methylation is involved in epigenetic processes such as X-chromosome inactivation, imprinting and silencing of transposons. DNA methylation is a highly plastic and critical component of mammalian development The DNA methyltransferases (Dnmts) are responsible for the generation of genomic methylation patterns, which lead to transcriptional silencing. The maintenance DNA methyltransferase enzyme, Dnmt 1, and the de novo methyltransferase, Dnmt3a and Dnmt3b, are indispensable for development because mice homozygous for the targeted disruption of any of these genes are not viable. The occurrence of DNA methylation is not random, and it can result in gene silencing The mechanisms underlying these processes are poorly understood. It is well established that DNA methylation and histone deacetylation operate along a common mechanistic pathway to repress transcription through the action of methyl-binding domain proteins (MBDs), which are components of, or recruit, histone deacetylase (HDAC) complexes to methylated DNA. As a basis for future studies on the role of the DNA-methyl-transferase in porcine development, we have isolated and characterized a partial cDNA coding for the porcine Dnmt1. Total RNA of testis, lung and ovary was isolated with TRlzol according to the manufacture's specifications. 5 ug of total RNA was reverse transcribed with Super Script II in the presence of porcine Dnmt 1 specific primers. Standard PCRs were performed in a total volume of 50 ul with cDNA as template. Two DNA fragmenets in different position were produced about 700bp, 1500bp and were cloned into pCR II-TOPO according to the manufacture's specification. Assembly of all sequences resulted in a cDNA from 158bp of 5'to 4861bp of 3'compare with the known human maintenance methyltransferase. Now, we are cloning the unknown Dnmt 1 region by 5'-RACE method and expression of Dnmt 1 in tissues from adult porcine animals.

The lutropin/choriogonadotropin receptor (LHR) is a member of the rhodopsin-like subfamily of G protein coupled receptor (GPCRs), that has been shown to mediate the internalization of its two naturally occurring agonist, lutropin and choriogonadotropin (CG). The clustered agonist-receptor complex is internalized by a dynamin-dependent pathway and traverses the endosomal compartment without agonist dissociation Dissociation of the agonist-receptor complex occurs in the lysosomes, where both the agonist and receptor are degrade. Recently, constitutively activating mutations of the receptor have been identified that are associated with familial male-precocious puberty (FMPP). A FMPP is a form of sexual precocious puberty in boys in which testosterone levels are elevated independent of changes in luteinizing hormone-releasing hormone and serum luteinizing hormone levels, We have now analyzed two naturally occurring, constitutively active mutants of the human LHR. These mutations were introduced into the rat LHR (rLHR) and are designated L435R and D556Y. Cells expressing rLHR-D556Y bind human choriogonadotropin (hCG) with normal affinity, exhibit a 25-fold increase in basal cAMP and respond to hCG with a normal increase in cAMP accumulation. Cells expressing rLHR-L435R also bind hCG with normal affinity, exhibit a 47-fold increase in basal cAMP, and do not respond to hCG with a further increase in cAMP accumulation. This mutation enhances the internalization of the free and agonist-occupied receptors ~2- and ~17- fold, respectively We conclude that the state of activation of the rLHR can modulate its basal and/or agonist-stimulated internalization. Since the internalization of hCG is involved in the termination of hCG actions, we suggest that the lack of responsiveness detected in cells expressing rLHR-L435R is due to the fast rate of internalization of the bound hCG. The finding that membranes expressing rLHR-L435R respond to hCG with an increase in adenylyl cyclase activity supports this suggestion. Autonomous Leydig cell activity in FMPP is caused by a constitutively activating LH/CGR.

Offspring have been produced from somatic cells in a number of species. This biotechnology introduced a new phenomenon in reprogramming and differentiation of somatic cell, namely totipotency. However, birth of oversized calves and perinatal abnormalities such as increased gestation length, lack of spontaneous parturition, higher incidence of dystocia, and reduced perinatal viability of offspring are frequently observed in pregnancies of cloned bovine fetuses. Disturbance of feto-placenta has been proposed as likely causes for abnomal growth. However. Little is known the mechanism responsible for the perinatal problems. Therefore, we focused on gestation length in somatic cell nuclear recipient cows. To solve this issues, placental tissues of control and cloned bovine were obtained by a cesarean section (C-section) before 5 days of paturition. Total RNA from control and cloned bovine placenta was extractd by TRIzol reagent. GeneFishing DEG kits (Seegene) were used to identify differentially expression genes. Total RNA (3 ug) were synthesized by M-MLV reverse transcriptase (200 u/ul) with 10 uM dT-annealing control primer (ACP1) at 42C for 90 min. Then, first-strand cDNA (50 ng) was amplified using the 5 uM arbitary ACP (1-20) and 10 uM dT-ACP2 primers. Some specific expression genes were amplified, Now, we are cloning and sequencing. These finding strongly can be support to solve the problems for parturition delay in nuclear transfer cows, suggest that placenta specific proteins are key indicators for the aberration of gestation and placental function in cows.

버어리종 신품종 육성을 위한 기초자료를 얻기 위하여 수량성ㆍ품질 및 내병성을 달리하는 Burley 21등 5품종을 full diallel cross하여 20개 F1 을 만들고 양친과 함께 공시하여 초장, 엽수 ; 초장ㆍ폭, 엽면적 및 개화일수 등 주요형질과 수량ㆍ품질에 관하여 유전력, 유전자의 분포상태 및 유전자 작용에 대하여 분석ㆍ검토한 결과를 요약하면 다음과 같다. 1. 8개 형질에 대한 협의와 광의 유전력은 각각 0.1618-0.6914와, 0.7494-0.9537 범위였으며 초장, 개화일수에서 가장 높았고 수량ㆍ품질에서 가장 낮았다. 2. 초장의 유전은 장간이 단간에 대하여 부분우성을 나타냈으며 우성유전자의 관여가 컸고 우성유전자는 increaser로 작용하였다. L8은 열성친으로 다른 4품종은 우성친으로 나타났다. 3. 엽수의 유전에는 상가적 유전자 작용이 컸고 다엽이 소엽에 대하여 부분우성이었으며 모체 품종중에는 우성과 열성유전자가 거의 동수로 분포하는 것으로 추정되었다. 4. 엽장은 장엽이 단엽에 대하여 완전우성 유전을 하는 것으로 추정되며, 엽폭에서는 광엽이 세엽에 대하여 초월우성을 보여 F1 의 엽면적 증대를 가져와 수량증가의 요인으로 작용하였다. 5. 개화기 유전은 조성이 만성에 대하여 부분우성으로 상가적 유전자의 작용이 컸고 관여하는 유효인자수는 1-2개 정도였으며 우성유전자는 개화기를 단축시키는 작용을 하였다. 6. 수량은 다수성이 우성인 초월우성유전을 보였으며, 품질은 질량이 우성인 완전우성 유전으로 추정되었다. L8은 두가지 형질에 대하여 열성친으로 나타났으며 4개 품종들은 우성친으로 나타났다.아질수록, 그리고 황산나트륨의 첨가시용으로 출수기 지엽의 광합성 용력이 증대되었으며 수원 26004가 진흥보다 그 반응이 더 뚜렷하였다. 5. 염록소 함량 및 건물중과 엽신의 황의 함량과는 정의 상관을 보였으며 수원 26004가 진흥보다 더 큰 상관을 보였다. 황산암모니아와 요소를 각각 연용해온 논에서의 시험은 1. 엽록소 함량 및 건물중은 황산암모니아 시용구에서 더 컸으며 수확기 볏짚중의 질소 및 주요 무기성분의 함량은 황산암모니아구가 커서 양분의 잠재능력이 요소구보다 컸다. 2. 황산암모니아의 시용은 수수 및 등숙율을 높히는 경향이었고 통계적인 유의차는 없었으나 수량이 증대되었다.s-U601, -U603, -U604와 -U171은 성장을 더 이상하지 않았다.ta-exotoxin을 생산했는데, 48시간 배양 배지 m 당 70ug을 분비한 균주는 BTK-1이고, BTK-37 균주는 m 당 88ug(6.1 108 Cells/m ) BTK-35 균주는 m 당 81ug(5.2 108 Cells/m )을 생산했고. 그외는 모두 70ug미만이었다. 3. Beta-exotoxin과 B. thuringiensis 균체을 동시에 per os, interaperi

수집된 재래의 유색대두종을 일률적인 재배조건하에서 종실특성 변이와 종실종군별 생육진전 및 수량형질 특성을 조사한 결과 다음의 결론을 얻었다. 1. 유색대두 수집종들은 100립중을 기준으로 하여 20gr 이하의 소립중, 20-25gr의 중립중, 25-30gr의 대립종 및 30gr 이상의 특대립종 등 4개군으로 나눌 수 있었다. 2. 종실크기에 관련된 요인중 종실장과 종실폭의 변이는 종실후보다 크게 나타났다. 3. 종실중과 경중 및 주당협수 등의 형질들은 변이계수에서 생육일수나 결과일수 등의 형질보다 큰 경향이었다. 4. 생육일수와 성숙일수 및 개화시기는 립중군별간에 유의한 차이를 나타내지 않았다. 5. 개화기와 성숙일수는 경장 및 경중과 정의 상관관계를, 경장과 경중은 수량형질과 정의 상관을 나타내었으며, 주당협수는 100립중과 부의 상관을, 또한 수량과는 정의 상관관계를 나타내었다.