Studies on spatio-temporal regulation mechanisms of GnRH gene expression

Gonadotropin-releasing hormone (GnRH) is a pivotal hypothalamic neurohormone governing reproduction and sexual development. Extensive studies thus for have been undertaken to characterize GnRH neuron-specific enhancers in distal promoter regions of the mammalian GnRH genes since immortalized GnRH neuronal cell lines such as GT1 and Gn11 became available. However, these previous works still cannot fully account for spatio-temporal regulation of GnRH gene expression taking place in a highly restricted population of hypothalamic neurons. There are only few of trans-acting factors and their binding cis-elements on the GnRH promoter are characterized, suggesting that as yet undiscovered transcription factors and their evoked mechanisms may underlie the cell type specificity of GnRH gene expression. In terms of temporal regulation, GnRH is known to release in a pulsatile manner, however no evidence of whether oscillatory secretion is related to transcriptional regulation of GnRH is available thus far. In this regard, I examined the spatio-temporal regulation of GnRH gene expression. In Chapter I, I aimed to elucidate the novel transcriptional regulation mechanisms of neuron-specific GnRH gene expression. Up to now, a region approximately 3.0 kb upstream of the mammalian GnRH promoter has been extensive studied, but these results can not fully account for the GnRH neuron specificity. Here I demonstrated a transcription-enhancer located in the first intron (intron A) region of the GnRH gene. This transcriptional enhancer harbors putative Sry-related high-mobility-group box (SOX) family transcription factor-binding sites, which are well-conserved across mammalian species. The class-C SOX member proteins (SOX-C; SOX4 and SOX11) specifically augmented this transcriptional activation by binding to these SOX-binding sites. Accordingly, SOX11 was highly enriched in immortalized GnRH-producing GT1-1 cells, and suppression of its expression significantly decreases GnRH gene expression and subsequent GnRH secretion. Chromatin immunoprecipitation (ChIP) revealed that endogenous SOX-C factors recognize and bind to the intronic enhancer in GT1-1 cells and the hypothalamic tissue. Immunohistochemical analysis showed that SOX4 or SOX11 are highly expressed in the majority of hypothalamic GnRH neurons in adult mice. Consequently, these findings suggest that SOX-C transcription factors function as important transcriptional regulators of cell type-specific GnRH gene expression by acting on the intronic transcriptional enhancer. In Chapter II, I aims to examine whether the chromatin remodeling mechanism are involved in the ultradian rhythmicity of GnRH transcription. To determine whether the GnRH gene expression show rhythmic oscillations at the level of gene transcription, GnRH primary transcript levels were measured in GT1 cells after a serum treatment for synchronization. Primary transcript levels of GT1 cells exhibited rhythmic oscillation in an hour interval and this rhythm was not abolished by inhibition of translation. But the oscillation was profoundly disrupted by the changes of histone acetylation and methylation states. ChIP assay revealed that histone acetylation and methylation also showed ultradian kinetics in the GnRH genomic regions. Furthermore, histone methylations in the transcription start site of GnRH gene showed antiphasic oscillations between transcriptional active (H3K4-Me3) and repressive (H3K9-Me2) histone markers. This novel mechanism may underlie the ultradian regulation of GnRH gene transcription.Docto

2016년 제2차 디지털의료기기 지식연구회 - ICT기반 헬스케어산업의 발전방향 -

◦ 행사명 : 2016년 제2차 디지털의료기기 지식연구회 ◦ 일 시 : 2016년 7월 27일(수) 15:00 ~ 17:30 ◦ 장 소 : EXCO 503호 회의실 ◦ 참석대상 : (주)메가젠임플란트 등 회원사 15명 ◦ 주요내용 : 1. ICT기반 헬스케어산업의 발전방향 (대구디지털산업진흥원 김희대 팀장) 2. 웰니스 산업현황 및 발전방향 (첨단의료기기개발지원센터 최문종 팀장) 3. 의료분야 3D프린팅 기술 및 주요동향 (첨단정보통신융합산업기술원 박현위 팀장

실시간 멀티미디어 트래픽 관리를 위한 개선된 RTP 패킷 분류 방법

학위논문(석사)--아주대학교 정보통신전문대학원 :정보통신공학과,2003Maste

Ion acoustic wave measurement using multi-dipole doubleplasma device

Maste

클러스터 진화과정과 기업의 네트워킹전략에 관한 연구

학위논문(박사) - 한국과학기술원 : 기술경영학과(IT경영학), 2014.2, [ v, 89 p. ]The industry cluster, one of the critical environmental factors for companies to grow, has experienced through the process of constant evolution over time. The latest developments of information and communication technologies and the enhancement of network tools have enabled the virtualization of the physical effects of cluster - spillover of knowledge, supporting resources, spaces, money, and surplus labor - which are included in the industry cluster. The cluster effect that was considered one of the exogenous strategy factors has been changed into an outsourcing and endogenous capacity factor through experiencing implementation or modularization by firms and agencies with utilizing information communi-cation and network technology. These capacities of implementation and modularization to make business ecological environment, so-called business platform or virtual cluster, can be the vital factor to determine the sustainability of innovative firms and agencies today. The de-velopments of web technologies (Web 2.0, Web 3.0 and etc.) have become carriers for operat-ing open innovation through learning and surplus of knowledge. Based on this background, this thesis has significance to clarify the process of evolution of industrial clusters and the driving factors to enable the virtual cluster, and to elicit networking strategies for firms’ growth in the cluster. The first essay shows the process of evolution in the software industrial cluster which is one of the representative examples of the knowledge industry by analyzing the correlation between the changes of firms’ networking structural changes and performances over time. The software industry forms geographic clusters with linkages and sharing of knowledge and it demonstrates a unique industrial cluster network structure caused from its network externality and exclusive nature. Analyzing network structure with the cross-section data of participants’ collaboration, information sharing, and networking activi...한국과학기술원 : 기술경영학과(IT경영학)

Schizosaccharomyces pombe의 Sen1 단백질의 helicase활성 연구

학위논문(박사) - 한국과학기술원 : 생물과학과, 1998.8, [ viii, 121 p. ]A DNA and RNA helicase was purified from extracts of Schizosaccharomyces pombe to near homogeneity. The helicase activities copurified with a 95-kDa polypeptide upon a SDS-polyacrylamide gel electrophoresis. Determination of its partial amino acid sequence and molecular masses of its trypsin-digested peptides revealed that the enzyme is homologous to the SEN1 gene product of Saccharomyces cerevisiae, an essential protein affecting a variety of RNA metabolisms in a global fashion including endonuclease cleavage of introns from precursor tRNAs in yeasts. Thus, the purified enzyme was named SpSen1p (Sen1p of Schizosaccharomyces pombe). This study first demonstrated that SpSen1p is indeed a DNA and RNA helicase as inferred from the fact that SEN1 of Saccharomyces cerevisiae shares sequence homology to Upf1, previously known as an RNA and DNA helicase. In addition, various biochemical parameters associated with the enzyme were determined in detail. The helicase utilized partial duplex substrates with free 5``-single-stranded tails, demonstrating that it translocated with the exclusive directionality of a 5`` to 3``. SpSen1p was capable of unwinding all four combinations of DNA and RNA duplexes. In agreement with this observation, SpSen1p hydrolyzed ATP in the presence of either DNA or RNA as cofactor. Among polynucleotide cofactors tested, yeast tRNA was least efficient in supporting ATP hydrolysis of SpSen1p. RNA substrate was unwound more efficiently (2-fold) by SpSen1p than DNA substrate in the absence of salt. However, in the presence of salt (25-50 mM), both DNA and RNA substrates were unwound equally well. The enzyme has higher affinity (5-8 fold) towards single-stranded DNA than single-stranded RNA, whereas RNA was preferred substrates for unwinding. This observation indicates that stronger affinity towards DNA could hinder the enzyme``s ability to translocate along DNA, thereby lowering unwinding efficiency of DNA substrate. Purification of a larger version ...한국과학기술원 : 생물과학과

돌연변이에 의한 파필로마바이러스 URR 부위의 전사 조절 기작

학위논문(석사) - 한국과학기술원 : 생명과학과, 1994.2, [ iii, 48 p. ]The upstream regulatory region (URR) of the bovine papillomavirus type 1 (BPV-1) genome can function as a conditional transcriptional enhancer that can be specifically trans-activated by the viral E2 gene product. By the use of a linker scanning mutagenesis, the URR of BPV-1 was introduced double-stranded BamHI linker (5``-CGGATCCG-3``) at discrete locations without causing the addition or deletion of other sequences. These mutants of the URR were analyzed for their activity to enhance the activity of transcription from the promoters $P_{7940}$ and $p_{89}$ in the presence of the viral E2 gene product. The nucleotide sequences in the E2-responsive element 2 (E2RE2), even in one of the E2 binding site, were found to be replaceable. While the nucleotide sequences between the two paired E2 binding sites in E2RE1 were replaceable, the E2 binding site 10 and the 3`` boundary region of E2RE1 were proved to be necessarily critical to mediate the trans-activation. The finding that the replacements of the consensus recognition sequences for Sp1 and CCAAT-binding transcription factor (CTF) around the $P_{7940}$ promoter severely affected transcription indicates that the interaction between the viral E2 transactivator and the cellular transcription factors bound at the $P_{7940}$ promoter cis-elements are very important to activate the E2-responsive transcription.한국과학기술원 : 생명과학과