Identification of H3K4me1-associated proteins at mammalian enhancers.

Enhancers act to regulate cell-type-specific gene expression by facilitating the transcription of target genes. In mammalian cells, active or primed enhancers are commonly marked by monomethylation of histone H3 at lysine 4 (H3K4me1) in a cell-type-specific manner. Whether and how this histone modification regulates enhancer-dependent transcription programs in mammals is unclear. In this study, we conducted SILAC mass spectrometry experiments with mononucleosomes and identified multiple H3K4me1-associated proteins, including many involved in chromatin remodeling. We demonstrate that H3K4me1 augments association of the chromatin-remodeling complex BAF to enhancers in vivo and that, in vitro, H3K4me1-marked nucleosomes are more efficiently remodeled by the BAF complex. Crystal structures of the BAF component BAF45C indicate that monomethylation, but not trimethylation, is accommodated by BAF45C's H3K4-binding site. Our results suggest that H3K4me1 has an active role at enhancers by facilitating binding of the BAF complex and possibly other chromatin regulators

東澳嶺崩塌地之地形演育分析

梅姬颱風 (2010) 與東北季風之共伴效應於台灣宜蘭縣蘇澳地區帶來了豐沛降雨，高累積雨量造成了台9 線蘇花公路群集性土砂災害，尤其在115.9K 上邊坡更誘發了約210 萬m3 之大規模崩塌土砂災害。本文從現地地質調查、致災機制、水文分析及遙測影像判釋等面向進行討論。由降雨-延時-頻率分析得知近年來誘發重大崩塌事件的雨量皆高於200 年回歸週期，並獲致良好判別致災雨場之I-R 圖降雨臨界線關係(Re+53.5Iave=1,146)。多時期遙測影像判釋指出東澳嶺坡頂之弧型張力裂隙仍有持續溯源發展之趨勢。裸露崩塌地不連續面方位密度分布圖之裂隙位態大致與區域地質構造位態 (N70°W) 相近，顯示本區域崩塌主要仍受地質條件主控。此外，蝕溝溯源侵蝕、剪裂帶分布及凹漥坡型亦為影響研究區崩塌地地貌變遷之重要因子，而前期地震或長延時高強度降雨則為外在促崩因子。Typhoon Megi coupled with the northeastern monsoon induced an extreme rainfall of 939 mm on the Suao area, Yilan County, in eastern Taiwan on October 21st, 2010, causing the Dong-Ao Peak landslide of 2.1 million m3 along the coastal Su-Hua Section of Highway Route 9. This study adopts a geological survey, rainfall data, satellite images, orthophotos, and high-resolution DEM based on airborne laser scanner surveys to quantify the morphological changes before and after landslide events following major rainfall events since 2010. Rainfall frequency analysis indicates the cumulative precipitation triggering landslide events is greater than the 200-year return period. In addition, both the entrainment effect of debris flow and toe erosion on the down-slope is shown to induce regressive sliding failure at the adjacent roadbed. The results suggest that geological factors such as head-cutting erosion and the concave landform shape the landform evolution of the catchment. The occurrence of landslides also depends on antecedent earthquake events and extreme intense rainfalls

Erratum for Edwards et al., “Draft genome sequence of uncultured upland soil cluster Gammaproteobacteria gives molecular insights into high-affinity methanotrophy”

Erratum for Edwards et al., “Draft Genome Sequence of Uncultured Upland Soil Cluster Gammaproteobacteria Gives Molecular Insights into High-Affinity Methanotrophy”

An Algorithm for Preferential Selection of Spectroscopic Targets in LEGUE

We describe a general target selection algorithm that is applicable to any survey in which the number of available candidates is much larger than the number of objects to be observed. This routine aims to achieve a balance between a smoothly-varying, well-understood selection function and the desire to preferentially select certain types of targets. Some target-selection examples are shown that illustrate different possibilities of emphasis functions. Although it is generally applicable, the algorithm was developed specifically for the LAMOST Experiment for Galactic Understanding and Exploration (LEGUE) survey that will be carried out using the Chinese Guo Shou Jing Telescope. In particular, this algorithm was designed for the portion of LEGUE targeting the Galactic halo, in which we attempt to balance a variety of science goals that require stars at fainter magnitudes than can be completely sampled by LAMOST. This algorithm has been implemented for the halo portion of the LAMOST pilot survey, which began in October 2011.Comment: 17 pages, 7 figures, accepted for publication in RA

Gene Expression Profiling of Biological Pathway Alterations by Radiation Exposure

[[abstract]]Though damage caused by radiation has been the focus of rigorous research, the mechanisms through which radiation exerts harmful effects on cells are complex and not well-understood. In particular, the influence of low dose radiation exposure on the regulation of genes and pathways remains unclear. In an attempt to investigate the molecular alterations induced by varying doses of radiation, a genome-wide expression analysis was conducted. Peripheral blood mononuclear cells were collected from five participants and each sample was subjected to 0.5 Gy, 1 Gy, 2.5 Gy, and 5 Gy of cobalt 60 radiation, followed by array-based expression profiling. Gene set enrichment analysis indicated that the immune system and cancer development pathways appeared to be the major affected targets by radiation exposure. Therefore, 1 Gy radioactive exposure seemed to be a critical threshold dosage. In fact, after 1 Gy radiation exposure, expression levels of several genes including FADD, TNFRSF10B, TNFRSF8, TNFRSF10A, TNFSF10, TNFSF8, CASP1, and CASP4 that are associated with carcinogenesis and metabolic disorders showed significant alterations. Our results suggest that exposure to low-dose radiation may elicit changes in metabolic and immune pathways, potentially increasing the risk of immune dysfunctions and metabolic disorders.[[notice]]補正完畢[[incitationindex]]SCI[[incitationindex]]EI[[booktype]]電子

台2線 68K 八斗子滾石災害致災成因初探

基隆市北寧路於2013 年8 月31 日下午發生高強度降雨事件 (最高達94.5 mm/hr)，並導致台2 線68K+000 處於當日16 時19 分左右發生落石擊毀小客車之意外。本次落石災害之發生區屬於大寮層中段塊狀砂岩，且為逆向坡之型態，現地調查結果顯示本區域具有兩組傾角近乎垂直之節理面，一組走向約略平行於海岸線，另一組走向則約略垂直於海岸線。致災成因可能與長期雨水入滲及風化作用有關，節理裂隙除因風化作用逐漸加大外，節理面上之含鐵質結核亦可能於風化後體積增加，進而加速節理開裂速度。本次落石災害之運動歷程大致可分為傾倒、滾動、墜落、彈跳、滾動等數段歷程，落石運動過程耗時約23 秒，移動路徑上之植被與風化土壤層可能為遲滯落石運動之主因。本文將說明此次災害之地質調查成果，並探討可能之破壞機制，以供未來類似災害之防治對策參考。Several rockfalls caused damages on Highway No.2 during an intensive rainfall on August 31, 2013, in Keelung. One of the rockfalls hit a car and the event was captured by a camera. This study analyzes the mechanism of the rockfall based on the video and field investigation. Two major joints which led to the hazard, one was parallel to the coast and the other was perpendicular to the coast. Both of them were almost vertical and cut the rock into several blocks. Weathering processes may have lead to the extension of joints during the heavy rainfall; the infiltration and the surface runoff took the weathered material away, making the rock unable and ultimately leading to the rockfall. The process of this hazard can be divided into topple, roll, fall, bounce and roll. The rockfall took about 23 seconds in total. This paper focuses on the results of field investigation and the mechanism of the rockfall is also discussed