Histone Lysine Methylation

곽상준,Kwak, Sahng-June Korean Society of Life Science 2007 생명과학회지 Vol.17 No.3

유핵세포의 게놈(genome)은 단백-DNA복합체인 염색질(chromatin)의 형태로 존재하는데, 생명현상을 유지하기 위해서는 생명체 또는 세포가 처한 상황에 맞게 염색질의 구조를 변화시키는 역동적인 조절기전이 필요하다. 염색질을 구성하는 기본단위는 히스톤 8량체 (histone octamer)를 포함하는 뉴클레오좀(nucleosome)이다. 히스톤 단백에는 여러 종류의 공유결합성 수식이 일어나는데, 그 중 하나가 라이신 잔기(lysine residue)에 일어나는 메틸화이다. 최근 수년간의 연구로 여러 개의 히스톤 라이신 메틸화효소(histone lysine methyltransferase, HKMT), 이에 결합하는 염색질단백 및 메틸화와 관련된 후생유전학적 현상이 밝혀졌으며, 특히 정밀한 연구방법을 동원한 다방면의 실험을 통하여 비록 자세한 기전과 전체적인 윤곽의 규명은 미흡하더라도 라이신 메틸화가 후생유전학적 변화를 초래하는 일부 과정이 규명 되었다. 또한 여러 종류의 라이신 탈메틸화효소가 최근에 발견됨에 따라, 아세틸화, 인산화등 다른 공유결합성 수식보다는 상대 적으로 안정되더라도, 히스톤 메 틸화로 유발되는 후생유전학적 변화가 불가역성이 아님을 알게 되었다. Our genome exists in the form of chromatin, and its structural organization should be precisely regulated with an appropriate dynamic nature for life. The basic unit of chromatin is a nucleosome, which consists of a histone octamer. These nucleosomal histones are subject to various covalent modifications, one of which is methylation on certain lysine residues. Recent studies in histone biology identified many histone Iysine methyltransferases (HKMTs) responsible for respective lysine residues and uncovered various kinds of involved chromatin associating proteins and many related epigenetic phenotypes. With the aid of highly precise experimental tools, multi-disciplinary approaches have widened our understanding of how lysine methylation functions in diverse epigenetic processes though detailed mechanisms remain elusive. Still being considered as a relatively more stable mark than other modifications, the recent discovery of lysine demethylases will confer more flexibility on epigenetic memory transmitted through histone lysine methylation. In this review, advances that have been recently observed in epigenetic phenotypes related with histone lysine methylation and the enzymes for depositing and removing the methyl mark are provided.

Current Progress in Generation of Genetically Modified Mice

송기덕,조병욱,Song, Ki-Duk,Cho, Byung-Wook Korean Society of Life Science 2007 생명과학회지 Vol.17 No.4

Manipulation of the mouse genome by activating or inactivating the gene has contributed to the understanding of the function of the gene in the subset of cells during embryonic development or postnatal period of life. Most of all, gene targeting, which largely depends on the availability of mouse embryonic stem (ES) cells, is the milestone of development of animal models for human disease. Recombinase-mediated genome modification (Cre-LoxP and Flp-Frt etc) and the ligand-dependent regulation system, more accurate and elaborate manipulation tools, have been successfully developed and applied to dissect the mechanisms governing complex biological processes and to understand the role of protein in temporal-and spatial aspects of development. As technologies concerning refined manipulation of mouse genome are developed, they are expected to open new opportunities to better understand the diverse in vivo functions of genes. 생쥐 유전자를 과발현 시키거나 제거하는 유전자 조작 기술의 발달은 배 발생 단계나 출생 후 특정한 세포에서의 특정 단계에서의 유전자 기능을 이해하는 많은 기여를 하고 있다. 특히, 높은 상동 재조합 활성을 가지는 생쥐 배 줄기세포를 이용한 유전자 적중 기법은 인간 질환을 이해하는데 필수적인 동물 모델 개발에 중요한 기여를 하였다. 최근에는 Cre과 Flp와 같은 염기서열 특이적 재조합 효소와 라이겐드에 의한 조절 시스템의 도입으로 좀 더 정확하고 정교한 유전자 발현 조절을 위해 개발되어 복잡한 생명현상을 지배하는 메카니즘과 시간과 공간에서 작동하는 유전자의 기능을 이해하는데 많은 기여를 하고 있다. 마우스 게놈을 세밀하게 조작할 수 있는 새로운 분자생물학적 도구의 적용으로 in vivo상에서 유전자의 다양한 기능을 좀 더 정확하게 이해할 수 있는 기회가 열릴 것으로 기대된다.

Expression analysis of RBMY1, CDY1, and VCY2 genes in Korean male infertility

허재원,김우영,김대수,하홍석,박남철,최욱환,남기만,최진,김희수,Huh, Jae-Won,Kim, Woo-Young,Kim, Dae-Soo,Ha, Hong-Seok,Park, Nam-Chul,Choi, Ook-Hwan,Nam, Ki-Man,Choi, Jin,Kim, Heui-Soo Korean Society of Life Science 2007 생명과학회지 Vol.17 No.5

무정자증에 영향을 미치는 AZFa, b, c 영역은 남성불임환자에서 잦은 미세결실이 발견됨으로써 정자형성과정에서 중요한 역할을 할 것으로 주목 받아왔다. 이들 영역에 있는 유전자중 RBMY1, CDY1 그리고 VCY2유전자는 고환에서 남성의 생식선 세포의 분화와 연관되어 있는 것으로 알려졌다. 42명의 무정자증 환자의 고환조직을 RT-PCR법으로 분석해본 결과 RBMY1, CDY1 그리고 VCY2 유전자는 각각 34%, 66%, 그리고 27%의 환자에서 발현되지 않는 것으로 조사되었다. RBMY1 과 VCY2유전자가 발현되지 않는 개체는 CDY1유전자도 역시 발현이 되지 않았다. 세르토리 세포만 가진 환자에서는 CDY1 유전자가 발현되지 않았다. 따라서, CDY1 유전자는 한국인 집단에서 정자형성과정의 필수적인 요인인 것으로 사료된다. Azoospermia factor(AZFa, b, and c) regions have been focused on their involvement in the spermatogenic process by frequent observation of microdeletion in male infertility. Among the azoospermia factors, RBMY1, CDY1, and VCY2 genes are strongly associated with the male germinal cell differentiation and development in testis. Using RT-PCR approach, expression patterns of RBMY1, CDY1, and VCY2 genes are examined in testicular biopsy specimens from 42 Korean azoospermic patients. No expression of RBMY1, CDY1, and VCY2 genes appeared as 34%, 66%, and 27% of the male infertility, respectively. Patients who had no expression of RBMY1 and VCY2 genes also showed negative expression of the CDY1 gene in their testis tissues. All Sertoli cell-only syndrome patients showed no expression of the CDY1 gene. Taken together, the CDY1 gene expression seems to be necessary factor to complete spermatogenesis in Korean population.

Phylogenetic Relationship among Several Korean Coastal Red Tide Dinoflagellates Based on their rDNA Internal Transcribed Spacer Sequences

Cho, Eun-Seob,Kim, Gi-Yong,Park, Hyung-Sik,Nam, Byung-Hyouk,Lee, Jae-Dong Korean Society of Life Science 2001 Journal of Life Science Vol.11 No.2

The nucleotide sequences of the internal transcribed spacer regions (ITS1 and ITS2) of ribosomal DNA (rDNA), and the 5.85 rRNA gene, have been determined for 13 strains of dinoflagellates in order to analyze the phylo-genetic relationship. The DNA sequences contained considerable variation in the ITS regions, but little in the 5.85 rDNA. In addition, the ITS1 was more variable than the ITS2 in all species examined. The nucleotide length of this region varied from 519 bp to 596 bp depending on the taxa. The investigated taxa were divided into three large groups based on the ITS length, i. e., a group with short ITS region (A. fraterculus and Alexandrium sp.), a with ITS region group (P. micans, P. minimum and P. triestinum) and a with ITS region group (G. impudicum, C. polykrikoides, G. sanguineum, G. catenatum and H. triquetra). The relationship between nucleotide length of ITS1 and that of ITS2 was negative, whereas G+C content and nucleotide length showed positive correlation. In phylogenetic analyses producing NJ trees, the topology was similar cluster and clearly divided the taxa into three groups based on 5.8S rDNA that were similar to those based on morphological characteristics. In particular, G. impudicum was more closely related to G. catenatum than to C. polykrikoides using phylogenetic analysis. From this study, we chew that the length of ITS region contributes to discriminate Korean harmful algal species and ITS analysis is a useful method for resolving the systematic relationships of dinoflagellates.

Genetic Variation and Population Structure of Alder (Alnus hirsuta : Betulaceae) in Korea

Park, Joo-Soo,Huh, Man-Kyu Korean Society of Life Science 2000 Journal of Life Science Vol.10 No.1

Variation at 25 allozyme loci in Korean wateralder (Alnus hirsuta Rupr.) from nine distinct populations was measured to estimate the amount and pattern of genetic diversity and population structure. The mean genetic diversity within population was 0.166. Korean alder populations have slightly high levels of genetic diversity compared to those present in associated temperature-zone species and two Canadian alder species. Among population s genetic differentiation accounted for an significant 9% of the total variation. High gene flow(Nm=2.63) was observed. Analysis of fixation indices, calculated for all polymorphic loci in each population, showed a substantial deficiency of heterozygotes relative to Hardy-Weinberg expectations. The mean GST value A. hirsuta in Korea (GST = 0.087) is similar to those of A. rogosa in Canada (GST = 0.052). These low values of GST in two countries. reflecting little spatial genetic differentiation, may indicate extensive gene flow (via pollen and/or seeds) and/or recent colonization. These factors reduce the effect of geographic isolation of breeding and the chance for genetic divergence. A pattern of increasing is observed with increasing rainfall per year. Regression analysis indicates that 54% (F = 4.67) of the variability observed can be explained by this relationship.

Molecular phylogeny of moon jellyfish Aurelia aurita Linnaeus collected from Yeosu waters in Korea based on nuclear and mitochondrial DNA sequences

김숙양,조은섭,Kim, Sook-Yang,Cho, Eun-Seob Korean Society of Life Science 2007 생명과학회지 Vol.17 No.3

본 연구는 여수연안해역에서 채 집 한 보름달 둥근 물해파리를 대상으로 ITS 부위와 미토콘드리아 유전자 염기서열을 이용하여 계통유연관계를 보왔다. ITS 부위를 증폭시키 기 위하여 F5와 R5 primer, 미토콘드리아 COI 유전자 증폭을 위하여 LCO1490과 HCO2198 primer를 사용했다. 증폭은 ITS에서 267 bp, COI에서 643 bp로 나타났다. 한국산 물해파리와 미국 캘리포니아에서 채집한 Aurelia sp.가 유전적 거리가 가장 짧은 0.023을 보인 반면에, 한국산과 미국산, 스웨덴산 물해파리는 동일한 종이지만 유전적 거리가 0.393에서 0.395로 매우 먼 것으로 나타났다. COI유전자의 경우 한국산과 영국산, 터어키산, 스웨덴산, 미국산 물해파리의 유전적 거리 범위는 0.201에서 0.205로 나타났다. 그러나 한국산과 미국산의 bootstrap은 100% 자매군으로 보였다. COI 유전자에 대한 한국산과 미국산 2차 RNA folding 구조를 볼 때 동일한 에너지 하에서도 상이한 2차 folding을 보였다. 따라서 ITS1과 COI 유전자는 보름달 둥근 물해파리 개체군의 생물지리학적 분포 조사를 위하여 유용한 도구로 활용될 것으로 추측된다. This study presents the molecular phylogenetic analysis of Korean Aurelia aurita Linnaeus collected from Yeosu in the southern waters of Korea using nuclear ITS1 region and mitochondrial COI gene sequences. The use of oligonucleotide primers F5 (forward) and R5 (reverse) targeted to ITS1 and LCO1490 (forward) and HCO2198 (reverse) targeted to COI amplified 267 bp and 643 bp fragments, respectively. The shortest genetic distance towards the ITS1 region is estimated at 0.023 when comparing Korean A. aurita to Aurelia sp. collected from California, USA. In particular, Korean and American/Swedish A. aurita were located far away in terms of genetic distance, ranging from 0.393 to 0.395. On the other hand, the genetic distance between Korean and English/Turkish/Swedish/American A. aurita regarding the mitochondrial DNA COI gene ranged from 0.201 to 0.205. However, a sister-ship with Korean and American A. aurita showed an extremely high bootstrap value (100%). The predicted secondary RNA structure of the mitochondrial DNA COI gene showed many different folding structures with a similar energy between Korean and American A. aurita. These results suggest that ITS1 and the mitochondrial DNA COI gene could be used as genetic markers for identification of the biogeographic populations.

Population Genetic Structure of Japanese Anchovy (Engraulis japonicus) in Korean waters Based on Mitochondrial 12S Ribosomal RNA Gene Sequences

김진영,조은섭,김우진,Kim Jin Yeong,Cho Eun Seob,Kim Woo Jin Korean Society of Life Science 2004 생명과학회지 Vol.14 No.6

한국해역에 분포하는 멸치의 유전학적 특성을 연구하기 위하여 미토콘드리아 12S 리보좀 RNA 유전자배열 (339 bp)을 분석하였다. 황해남부, 제주연안, 남해동부 등 3지역의 시료로 부터 총 35 mtDNA의 haplotype을 구하였다. 황해남부에서 채집된 멸치의 AN8T103은 PAUP 분석에서 $0.2-4.1\%$로 분리되는 독립적인 계통을 보이므로서 다른 연구해역으로부터 유입된 개체군인 것으로 보이나 금후 추가연구가 필요하다. AN8T103을 제외한 유전자 다양성은 $0.3-3.8\%$로서 개체군 내 염기다양성은 0.015(황해), 0.013(제주도), 0.015(남해)로 나타났다. 암컷유전자이동은 상당히 높았으며(Nm=25.5-36.44), 지역간 유전자거리(FST)는 유의한 차를 보이지 않았다$(P>0.01)$. 이러한 결과는 한국해역에 서식하는 멸치가 지리적으로 무작위 분산된 개체군임을 암시한다. We used portions of mitochondrial 125 ribosomal RNA gene sequences (339 bp) to investigate the phylogenetic and population genetic characteristics of the Japanese anchovy, Engraulis japonicus, in Korean waters. A total of 35 mtDNA haplotypes were obtained from the samples collected in 3 locations (the southern area of the Yellow Sea, the western coast of Jejudo, and the eastern area of the South Sea) in Korean waters. One haplotype, AN8T103, obtained from the southern area of the Yellow Sea, was formed according to an independent phylogenetic individual in the PAUP analysis, which was separated from the others by a $0.2-4.1\%$ sequence divergence. This distinct haplotype appeared to be one that was carried by immigrants from another study area, but further study is necessary. Genetic divergence, except for AN8T103, was moderate to substantial $(0.2-3.8\%)$ and nucleotide diversity within populations was 0.015 for Yellow Sea, 0.013 for Jejudo, and 0.D15 for South Sea, respectively. The female gene flow was substantial or high (Nm=25.5-36.4), and the genetic distances between regions were not statistically significant $(P>0.01)$. These results indicated that the Japanese anchovy populations occurring in Korean waters were consisted of individuals randomly dispersed over geographic areas.

Antifungal Activity of Korean Radish (Raphanus sativaus L) Extracts Against Pathogenic Plant

Won, Hwang-Cher- Korean Society of Life Science 2003 생명과학회지 Vol.13 No.2

국내산 무의 추출물을 여러가지 Column과 HPLC를 이용하여 잿빛곰팡이 병원균에 대한 항 진균성 물질을 분리하였다. 투석튜브를 이용한 분리에서 이물질이 3.5kDa 이하의 저분자물질이며 또한 내열성 물질임을 확인하였다. 이물질들은 최소한 5종의 물질로 구성되어 있으며 이중 가장 항진균성이 강한 물질을 HPLC를 이용하여 순수 분리하였으며 잿빛곰팡이병에 감염된 식물에 적용한 결과 농약과 비슷한 효과를 나타내어 환경 친화적인 항진균 물질로서 사용가능성을 확인하였다. A study of the anti-fungal properties in Korean radish was conducted using a variety of purification procedures such as Extrelut column, RP(Reverse Phase) Cl8 Column Chromatography, HPLC etc. to separate anti-fungal substances from Korean radish juices to test them against a common gray mold called Botrytis cenerea. Dialysis tube operation showed that these substances were presumably thermostable compounds with low molecular mass (less than 3.5 kDa). Differences of anti-fungal activities depending upon types of radishes used did not show any noticeable variation. The antifungals were presumably composed of more than 5 compounds. Among these, the most anti-fungal fraction was analyzed by HPLC in which one peak was obtained. Disease-affected plants were inoculated with 10mg of Extrelut fraction and results showed similar anti-fungal activity to pesticides suggesting possible usage of these substances as environmentally friendly antibiotics.

GRP94는 thyroglobulin의 folding에 관여한다.

Seong, Yeon-Mun,Shong, MinHo,Kwon, O-Yu Korean Society of Life Science 1999 생명과학회지 Vol.9 No.1

Endoplasmic reticulum (ER)내에 단백질의 folding과 안정화에 관여하는 단백질을 molecular cha-perone이라고 한다. GRP94 역시 ER내에 존재하는 molecular chaperone으로 알려지고 있지만 갑상선세포에서 단백질의 folding에 관여한다는 증거는 아직 불충분하다. 본 설험은 molecular chaperone을 세포내에서 overexpression시킬 수 있는 system을 확립하였다. 그 중에서 GRP94가 단백질의 folding에 직접적으로 관여한다는 증거를 얻기 위하여, endogenous GRP94를 code한 cDNA를 overexpression vector에 의해서 forced expression시킴으로 신생thyroglobulin의 folding에 직접적으로 관여하는 증거를 immun-oprecipitation으로 증명하였다. Mammalial expression vectors containing GRP94, BiP, ERp72, and PDI, were introduced into FRTL5 cells. Transfected cells were selected by neomycin resistance for exogenously overexpressed proteins in the ER. The use of a reducible cross-linker, DSP, markedly improved the ability to detect noncovalent interactions of PDI, BiP and GRP94 with newly-synthesized thyroglobulin. Under normal conditions, GRP94 was found to associate transiently with early Tg folding intermediates, displaying interaction kinetics similar to those reported for another ER chaperones of BiP.

Comparison of Reproduction Systems of Genus Potentilla, Potentilla discolor in Korea and P. conferta in Mongol

허만규,Huh, Man-Kyu Korean Society of Life Science 2007 생명과학회지 Vol.17 No.9

한국의 솜양지꽃(Potentilla discolor) 9개 집단과 몽골의 양지꽃속 식물 종 P. conferta 두 집단을 이용하여 두 종의 생식계를 비교하였다. 분포지에서 19개 형태 형질을 조사하여 정량분석에 사용하였다. 형태 형질에서 두 종간 많은 형질에 대해 유의한 차이를 나타내었다. 주성분분석에서 마디간 길이와 뿌리의 길이와 개수 등에서 특히 유의한 차이를 나타내어 이들 두 종을 분류하는데 유의한 성분으로 판단된다. P. conferta에서 라메트의 수는 거리의 증가에 따라 현저하게 감소하나 P. discolor는 정규분포 모양의 곡선을 나타내어 $60{\sim}80$ cm에서 가장 많았다. 빛에 대한 감수성은 P. discolor가 P. conferta보다 내성을 가지나 가뭄에 대해서는 P. conferta가 P. discolor보다 더 높은 내성을 나타내었다 . 이는 사막에 근접한 건조한 지역에 적응한 형태로 판단되며 온대 지방인 우리나라에 분포하는 솜양지꽃에 비해 단위면적당 밀도가 높아 이웃간 거리가 짧아 짧은 라메트를 많이 가지며 라메트 수가 많아 영양번식이 더 많이 이루어지고 있음을 나타낸다. I investigated the reproduction system of nine natural populations of P. discolor in Korea and two Mongolian P. conferta populations. The measurements of 19 quantitative or qualitative morphological characters were taken on each of total individuals directly from their natural habitats. Multivariate principal component analyses (PCA) were conducted to detect differences among populations consid-ering several characters simultaneously of variances using the statistical analysis system. 19 morpho-logical characteristics between Korean Potentilla species and Mongolian Potentilla species showed a slight heterogeneity of variance. The length of internodes (LFL and LSI) and characteristics of root (LLR and NOR) were shown a significant difference between two species (P<0.05). The number of ra-mets in P. conferta decreased with increasing geographic distance from viviparity. However, P. discolor has most ramets at distance intervals $60{\sim}80$ cm. In light conditions, P. discolor was significantly less resilience than P. conferta. In drought conditions, although there was not shown significant difference, P. conferta was less resilience than P. discolor. The core analysis indicates that P. conferta is the more resistant species than P. discolor and usually propagates by clonal growth during several strong envi-ronmental disadvantages such as drought events.