nature中英文摘要 2007年5月24日

 

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Nature 447: 7143
24 May 2007
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[自然要览]

（选自英国Nature杂志，2007年5月24日出版）


封面故事：细胞膜曲率诱导的蛋白间吸引力
Aggregation and vesiculation of membrane proteins by
curvature-mediated interactions
细胞膜远不只是细胞外的一层包裹物，对其拓扑进行的重塑研究，将它们与内吞
作用、囊泡形成和蛋白分选等重要功能联系了起来。专门的蛋白能够感知和生成
膜曲率，指导膜的重塑。几种蛋白需要一起发挥作用才能完成这一任务，所以一
种比较普遍的效应被认为也在发挥作用。多年来，物理学家、数学家、材料科学
家和细胞生物学家对一种可能的普遍作用——完全由膜曲率诱导的蛋白之间的吸
引力进行了研究。但是，诱导蛋白间相互作用的膜曲率的性质、甚至它们之间的
相互作用是吸引还是排斥都仍然比较模糊。现在，计算机模拟显示，曲率诱导的
相互作用的确可以是一种吸引力，并且是强大的、很有力的吸引力，完全能够胜
任影响膜重塑的任务。本期封面图片所示为一个在协同分裂期间被衣壳所覆盖的
虚拟细胞膜。（Letter p. 461; News & Views）


纳米晶体单激子光增益成为可能（Nanocrystals for lasers）
Single-exciton optical gain in semiconductor nanocrystals
半导体纳米晶体有非常好的发光性能，所以具有用作容易采用基于溶液的方法来
处理的光学放大媒介的潜力。这种材料的可能应用包括微电子中的光互联、“芯
片实验室”（lab-on-a-chip）技术、以及量子信息处理。这些结构所存在的问
题是，一个晶体中至少需要存在两个激子（束缚在一起的电子-空穴对），才能
实现光增益，这个要求限制了其性能表现。在效果上相当于，在能够出现光放大
之前激子会相互湮灭。现在，这一障碍已经利用核与壳来自不同半导体材料、电
子和空穴彼此分开的纳米晶体克服了。这使得基于单激子的光增益成为可能，显
著增强了它们作为激光应用中实用光学材料的希望。（Article p. 441; News &
Views）


亨廷顿病的诱因（Trigger for Huntington’s）
OGG1 initiates age-dependent CAG trinucleotide expansion in somatic
cells
氧化损伤几十年来一直被与衰老和神经退化疾病联系在一起，但氧化与衰老之间
的生理联系却仍然不很清楚。现在，这种联系可能已经被找到了。亨廷顿病和其
他几种神经退化疾病涉及以三个核苷酸为一组的CAG重复序列的扩张。在人类亨
廷顿病的小鼠模型中，这种扩张在生命中期出现，并且在整个生命过程中继续。
这种扩张发生在终端分异的细胞中，与氧化损伤有关。Glycolase OGG1中所存在
的缺陷衰减依赖于年龄的重复扩张，而且因为OGG1是一种DNA修复酶，所以似乎
氧化损伤的畸形修复诱发了这种疾病。这项工作为停止或减缓这种疾病发病的药
物找到了可能的作用目标。（Article p. 447）


能够形成淀粉状纤丝的短肽及其晶体结构（One for the zipper）
Atomic structures of amyloid cross-  spines reveal varied steric
zippers
阿尔茨海默氏症和帕金森氏症等神经退化疾病与淀粉状纤丝在大脑中的沉积有
关。纤丝在结构上非常统一，看看产生它们的蛋白的多样性就知道了。现在，
Sawaya等人识别出了来自很多不同淀粉状疾病的能够形成纤丝的短肽，并且获得
了由它们当中的13种所形成的晶体的原子结构。迄今分析过的所有这些肽，都通
过形成“steric zipper”的变种而进行自组装。“steric zipper”是在酵母锯
蛋白Sup 35中首次发现的一种结构特征。这种“拉链”可能是淀粉状纤丝强度的
关键，是治疗干预的首要目标。（Article p. 453）


“灿烂的红色新星”——OT2006-1（Bright prospect）
An unusually brilliant transient in the galaxy M85
很多重要天文发现开始于一道转瞬即逝的光或一个射电源的发现。2006年1月在
室女座星团中的Messier 85星系中发现的异常明亮的光学瞬时天体OT2006-1因此
是天文学家非常感兴趣的。Kulkarni等人报告了这一新光源的发现及其前几个月
的情况。该光源比一颗新星要亮，但比一颗超新星要暗。对“哈勃太空望远
镜”、“斯皮策太空望远镜”和“钱德拉X-射线天文台”的档案资料所做的一番
搜索，没有发现其前身的任何迹象。这一结果及主星系的性质表明，两颗老恒星
的合并可能是这一“灿烂的红色新星”形成的原因。（Letter p. 458）


从环礁湖沉积芯推知强烈飓风的频率（Windy lagoon）
Intense hurricane activity over the past 5,000 years controlled by El
Ni?o and the West African monsoon
飓风的仪器记录比较短， 这也是为什么控制飓风活动的因素仍然不是很清楚的
一个原因。Jeffrey Donnelly 和 Jonathan Woodruff通过建立北大西洋西部热
带海域中飓风活动的一个长期记录已经解决了这一问题。与袭击波多黎各
Vieques岛的强烈飓风相关的风暴，在该岛的一个环礁湖中沉积了多层粗糙沙质
物。来自这一环礁湖的沉积芯被用来获取过去5000年强烈飓风袭击的频率。该记
录与热带非洲厄尔尼诺事件和降雨的记录惊人地相似，说明厄尔尼诺/南方涛动
及西非季风强度的变化，在控制热带北大西洋中强烈飓风频率上曾经扮演一个重
要角色。（Letter p. 465）


肢发育的原始性（Limbering up）
An autopodial-like pattern of Hox expression in the fins of a basal
actinopterygian fish
四足动物（陆生脊椎动物）的四肢通常被认为是这样一个类群的动物所独有的演
化创新。现在，对一种名为“匙吻鲟”（Polyodon spathula）的“活化石”的
鳍的发育过程中Hox基因的表达所做的一项研究表明，被认为是四足动物四肢特
征的基因表达和调控模式也见于处在演化树根部的条鳍鱼的鳍中。“匙吻鲟”是
2.5亿年前海洋中常见的一种类型的有骨鱼的少数遗迹之一。这项工作表明，肢
发育的某些方面是原始的，是所有有骨鱼共同的，但在斑马鱼等高度发达的鱼类
中已经丢失。这些结果与最近新的化石发现如Tiktaalik是一致的，它是一种显
示出骨骼从鱼类向四足动物渐进的鱼。（Letter p. 473）


代谢通道与生理时钟的耦合之谜（Clocking on）
Transcriptional coactivator PGC-1  integrates the mammalian clock and
energy metabolism
很多生理参数，如体温、血糖和心率，随生理时钟的24小时节律发生周期性变
化。代谢通道与生理时钟是怎样耦合到一起的一直是一个谜，但现在用小鼠所做
实验表明，代谢转录调控因子PGC-1alpha是一个关键因素。缺少PGC-1alpha的小
鼠表现出异常的昼间活动节律、体温和代谢速度。在机械层次上，PGC-1alpha通
过ROR家族的孤核受体的共激发来调控时钟基因表达。（Letter p.477; News &
Views）


肿瘤的“金蝉脱壳”之计（Evasive tumours）
Disulphide-isomerase-enabled shedding of tumour-associated NKG2D
ligands
若干高级肿瘤似乎通过脱掉与I-类 “主要组织相容性复合体”相关的可溶性配
体MICA（该配体使 NKG2D受体失去活性）来逃避天然杀手细胞的免疫识别。用肿
瘤细胞培养所做的新的研究工作表明，这一“金蝉脱壳”过程的机制涉及ERp5，
它是一种与内质网相关的蛋白异构酶。这表明，表面ERp5是阻止肿瘤逃避免疫系
统的治疗干预的一个战略目标。（Letter p. 482）


细胞分裂轴取向的控制（Cell division）
Experimental and theoretical study of mitotic spindle orientation
细胞分裂轴的取向是正常生长和发育的关键，因为它决定未来子细胞的命运。细
胞附着在其上的细胞外基质在决定分裂轴取向中发挥一个作用。研究人员将用
HeLa细胞所做实验与定量理论结合起来所做的研究表明，轴取向由皮层力发生器
根据来自细胞微环境几何的提示信息来控制。一个基于由力发生器在轴微管上所
施加的拉力的简单模型，能够定量描述很多不同几何中的轴取向。（Letter p.
493）




----------------------
NEWS AND VIEWS
----------------------
Laser technology: Less excitement for more gain    pp385 - 386
In theory, semiconductor nanocrystals are highly suitable laser
materials, not least because the colour of their light is tunable over
a wide range. In practice, they are difficult ― but not impossible ―
to deal with.
Todd D. Krauss
10.1038/447385a
http://www.nature.com/nature/journal/v447/n7143/full/447385a.html

Circadian rhythms: Metabolic clockwork    pp386 - 387
The 'body clock' regulates the daily cycles of many physiological and
metabolic processes, but just how is a mystery. New findings suggest
that the cycling of energy metabolism is mediated by an activator of
gene expression.
Benedetto Grimaldi and Paolo Sassone-Corsi
10.1038/447386a
http://www.nature.com/nature/journal/v447/n7143/full/447386a.html

Biophysics: Bending over to attract    pp387 - 389
What forces shape the membranes of the biological cell? A computer
simulation indicates that it is the concerted effort of many proteins,
mediated by the lipid bilayer that forms the membrane matrix.
Michael M. Kozlov
10.1038/447387a
http://www.nature.com/nature/journal/v447/n7143/full/447387a.html

Molecular medicine: MicroRNAs and the tell-tale heart    pp389 - 390
MicroRNAs are natural, single-stranded, small RNA molecules thought to
control gene expression. Four studies indicate that specific microRNA
sequences can regulate heart function in development and disease.
Kenneth R. Chien
10.1038/447389a
http://www.nature.com/nature/journal/v447/n7143/full/447389a.html

Condensed-matter physics: A superfluid is born    pp390 - 391
For most of its existence, a superfluid droplet leads an essentially
innocuous, classical life. But intense scrutiny reveals that the birth
of such droplets is a turbulent and unpredictable quantum affair.
Henk T. C. Stoof
10.1038/447390a
http://www.nature.com/nature/journal/v447/n7143/full/447390a.html

Molecular biology: RNA in control    pp391 - 393
In bacteria, some messenger RNAs can sense the need for their protein
product and accordingly regulate expression of their own genes. A
similar type of RNA regulation has now been revealed in higher
organisms.
Benjamin J. Blencowe and May Khanna
10.1038/447391a
http://www.nature.com/nature/journal/v447/n7143/full/447391a.html

50 & 100 Years Ago    p391
10.1038/447391b
http://www.nature.com/nature/journal/v447/n7143/full/447391b.html

Supernovae: Answers and questions    pp393 - 394
Do we understand the violent and cosmologically significant stellar
explosions known as type-Ia supernovae? Yes and no, as astronomers
participating in a conference in California agreed.
David Branch and Ken'ichi Nomoto
10.1038/447393a
http://www.nature.com/nature/journal/v447/n7143/full/447393a.html

Hydrology: Flood of data    p393
Tim Lincoln
10.1038/447393b
http://www.nature.com/nature/journal/v447/n7143/full/447393b.html

----------------------
INSIGHT
----------------------
INTRODUCTION
Epigenetics    p395
Alex Eccleston et al.
10.1038/447395a
http://www.nature.com/nature/journal/v447/n7143/full/447395a.html

Perceptions of epigenetics    pp396 - 398
Adrian Bird
10.1038/nature05913
Abstract:
http://www.nature.com/nature/journal/v447/n7143/abs/nature05913.html
Article:
http://www.nature.com/nature/journal/v447/n7143/full/nature05913.html

REVIEW ARTICLE
Transcription and RNA interference in the formation of
heterochromatin    pp399 - 406
Shiv I. S. Grewal and Sarah C. R. Elgin
10.1038/nature05914
Abstract:
http://www.nature.com/nature/journal/v447/n7143/abs/nature05914.html
Article:
http://www.nature.com/nature/journal/v447/n7143/full/nature05914.html

The complex language of chromatin regulation during
transcription    pp407 - 412
Shelley L. Berger
10.1038/nature05915
Abstract:
http://www.nature.com/nature/journal/v447/n7143/abs/nature05915.html
Article:
http://www.nature.com/nature/journal/v447/n7143/full/nature05915.html

Nuclear organization of the genome and the potential for gene
regulation    pp413 - 417
Peter Fraser and Wendy Bickmore
10.1038/nature05916
Abstract:
http://www.nature.com/nature/journal/v447/n7143/abs/nature05916.html
Article:
http://www.nature.com/nature/journal/v447/n7143/full/nature05916.html

Epigenetic inheritance in plants    pp418 - 424
Ian R. Henderson and Steven E. Jacobsen
10.1038/nature05917
Abstract:
http://www.nature.com/nature/journal/v447/n7143/abs/nature05917.html
Article:
http://www.nature.com/nature/journal/v447/n7143/full/nature05917.html

Stability and flexibility of epigenetic gene regulation in mammalian
development    pp425 - 432
Wolf Reik
10.1038/nature05918
Abstract:
http://www.nature.com/nature/journal/v447/n7143/abs/nature05918.html
Article:
http://www.nature.com/nature/journal/v447/n7143/full/nature05918.html

Phenotypic plasticity and the epigenetics of human disease    pp433
- 440
Andrew P. Feinberg
10.1038/nature05919
Abstract:
http://www.nature.com/nature/journal/v447/n7143/abs/nature05919.html
Article:
http://www.nature.com/nature/journal/v447/n7143/full/nature05919.html

----------------------
ARTICLES
----------------------
Single-exciton optical gain in semiconductor nanocrystals    pp441
- 446
Semiconductor nanocrystals seem good candidates for 'soft' optical
gain media, but optical gain and lasing is hard to achieve owing to a
fundamental optical effect, which involves the problem that at least
two excitons need to be present in a nanocrystal to achieve gain, and
this limits performance. Here the problem is circumvented by designing
nanocrystals with cores and shells made from different semiconductor
materials, and in such a way that electrons and holes are separated
from each other: this makes possible optical gain based on single
excitons, thereby significantly enhancing the promise of semiconductor
nanocrystals as practical optical materials for a wide range of lasing
applications.
Victor I. Klimov et al.
10.1038/nature05839
Abstract:
http://www.nature.com/nature/journal/v447/n7143/abs/nature05839.html
Article:
http://www.nature.com/nature/journal/v447/n7143/full/nature05839.html

OGG1 initiates age-dependent CAG trinucleotide expansion in somatic
cells    pp447 - 452
Several neurodegenerative diseases are caused by expansion of CAG
triplet repeats, and, using a mouse model of human Huntington's
disease, this study shows that this expansion occurs in mid-life and
continues throughout life; furthermore, the expansion occurs in
terminally differentiated cells. This is associated with oxidative
damage, and deficiency in OGG1, a DNA repair enzyme, attenuates
age-dependent repeat expansion ― thus it seems that aberrant repair
of oxidative damage is the basis for this disease.
Irina V. Kovtun et al.
10.1038/nature05778
Abstract:
http://www.nature.com/nature/journal/v447/n7143/abs/nature05778.html
Article:
http://www.nature.com/nature/journal/v447/n7143/full/nature05778.html

Atomic structures of amyloid cross-β spines reveal varied steric
zippers    pp453 - 457
Degenerative diseases such as Alzheimer's or Parkinson's are
associated with the misfolding of many diverse proteins, yet the
amyloid fibrils formed by all these proteins are similar. David
Eisenberg and colleagues have now identified 30 short fibril-forming
peptides implicated in a range of amyloid diseases and have solved 13
of their atomic structures, revealing variations in one common feature
― the 'steric zipper'.
Michael R. Sawaya et al.
10.1038/nature05695
Abstract:
http://www.nature.com/nature/journal/v447/n7143/abs/nature05695.html
Article:
http://www.nature.com/nature/journal/v447/n7143/full/nature05695.html

----------------------
LETTERS
----------------------
An unusually brilliant transient in the galaxy M85    pp458 - 460
S. R. Kulkarni and colleagues report the discovery of a mysterious
optical transient called M85 OT2006-1 in the outskirts of the
lenticular galaxy Messier 85 in the Virgo Cluster. Brighter than novae
and fainter than supernovae, it is unlikely to be a giant eruption
from a luminous blue variable star because no such star is known to be
there, but a possible origin is a stellar merger.
S. R. Kulkarni et al.
10.1038/nature05822
Abstract:
http://www.nature.com/nature/journal/v447/n7143/abs/nature05822.html
Article:
http://www.nature.com/nature/journal/v447/n7143/full/nature05822.html

Aggregation and vesiculation of membrane proteins by
curvature-mediated interactions    pp461 - 464
Specialized proteins can sense and create membrane curvature, and
direct membrane remodelling, linked to important cellular tasks such
as endocytosis and protein sorting; but whether such proteins might be
assisted by more generic, universal effects has been unclear. One of
the most sophisticated simulation tools available for the task has now
been used to confirm that that is indeed the case; membrane curvature
caused by simple protein adsorption can drive clustering of proteins
lacking any specific interactions, and even induce local membrane
transformation into vesicles.
Benedict J. Reynwar et al.
10.1038/nature05840
Abstract:
http://www.nature.com/nature/journal/v447/n7143/abs/nature05840.html
Article:
http://www.nature.com/nature/journal/v447/n7143/full/nature05840.html

Intense hurricane activity over the past 5,000 years controlled by El
Nino and the West African monsoon    pp465 - 468
To investigate the links between hurricane activity and climate, this
study has constructed a long-term record of intense hurricane activity
in the western tropical North Atlantic Ocean by taking sediment cores
from a lagoon on the island of Vieques in Puerto Rico, where sand is
deposited by hurricanes. The record shows striking similarities to
records of El Nino events and rainfall in tropical Africa, suggesting
that changes in the El Nino/Southern Oscillation and the strength of
the West African monsoon were important in controlling the frequency
of intense hurricanes in the tropical North Atlantic over the past
5,000 years.
Jeffrey P. Donnelly and Jonathan D. Woodruff
10.1038/nature05834
Abstract:
http://www.nature.com/nature/journal/v447/n7143/abs/nature05834.html
Article:
http://www.nature.com/nature/journal/v447/n7143/full/nature05834.html

Evolution of cooperation in a finite homogeneous graph    pp469 - 472
This study bridges two theoretical approaches to model the evolution
of cooperation: inclusive fitness models and evolutionary game theory.
Simple analytical conditions are found for the evolution of
cooperation for a large class of graphs.
Peter D. Taylor, Troy Day and Geoff Wild
10.1038/nature05784
Abstract:
http://www.nature.com/nature/journal/v447/n7143/abs/nature05784.html
Article:
http://www.nature.com/nature/journal/v447/n7143/full/nature05784.html

An autopodial-like pattern of Hox expression in the fins of a basal
actinopterygian fish    pp473 - 476
By comparison with modern fishes such as zebrafish, it has long seemed
that the limbs of tetrapods are evolutionary innovations unique to
tetrapods, but here Marcus Davis and colleagues instead studied
Hox-gene expression in the development of the fins of a 'living
fossil'. The paddlefish, common in the seas more than 250 million
years ago, has Hox-gene patterns long considered to be tetrapod
hallmarks, showing that some aspects of limb development are primitive
and common to all bony fish, but which have apparently been lost in
highly evolved fishes such as the zebrafish.
Marcus C. Davis, Randall D. Dahn and Neil H. Shubin
10.1038/nature05838
Abstract:
http://www.nature.com/nature/journal/v447/n7143/abs/nature05838.html
Article:
http://www.nature.com/nature/journal/v447/n7143/full/nature05838.html

Transcriptional coactivator PGC-1α integrates the mammalian clock and
energy metabolism    pp477 - 481
Here the metabolic transcriptional regulator PGC-1alpha is identified
as a component of the circadian clock in mammals, which regulates
glucose and lipid homeostasis and energy metabolism. Mice lacking
PGC-1alpha in their liver and muscle show abnormal daily rhythms of
activity, body temperature and metabolic rate, correlated with the
disruption of clock genes.
Chang Liu et al.
10.1038/nature05767
Abstract:
http://www.nature.com/nature/journal/v447/n7143/abs/nature05767.html
Article:
http://www.nature.com/nature/journal/v447/n7143/full/nature05767.html

Disulphide-isomerase-enabled shedding of tumour-associated NKG2D
ligands    pp482 - 486
A number of advanced tumours appear to evade immune recognition by
natural killer cells by shedding the soluble major histocompatibility
complex class-I-related ligand MICA, which inactivates the NKG2D
receptor. Now the mechanism of shedding is shown to involve the
protein disulphide isomerase ERp5.
Brett K. Kaiser et al.
10.1038/nature05768
Abstract:
http://www.nature.com/nature/journal/v447/n7143/abs/nature05768.html
Article:
http://www.nature.com/nature/journal/v447/n7143/full/nature05768.html

Redox-mediated substrate recognition by Sdp1 defines a new group of
tyrosine phosphatases    pp487 - 492
The stress-induced yeast MAPK phosphatase Sdp1 acquires enhanced
activity under oxidative conditions by forming an intramolecular
disulphide bond that is used to recognize a tyrosine-phosphorylated
substrate.
G. C. Fox et al.
10.1038/nature05804
Abstract:
http://www.nature.com/nature/journal/v447/n7143/abs/nature05804.html
Article:
http://www.nature.com/nature/journal/v447/n7143/full/nature05804.html

Experimental and theoretical study of mitotic spindle
orientation    pp493 - 496
The orientation of the cell division axis is critical for normal
growth and development as it determines the fate of future daughter
cells; and the extracellular matrix to which cells adhere to plays a
role in determining the orientation of the division axis. Here Bornens
and colleagues present a combination of experimental and quantitative
theory to show that spindle orientation is controlled by cortical
force generators; a simple model based on pulling forces exerted by
force generators on spindle microtubules can quantitatively describe
spindle orientations in many different geometries.
Manuel Thery et al.
10.1038/nature05786
Abstract:
http://www.nature.com/nature/journal/v447/n7143/abs/nature05786.html
Article:
http://www.nature.com/nature/journal/v447/n7143/full/nature05786.html

Control of alternative RNA splicing and gene expression by eukaryotic
riboswitches    pp497 - 500
Riboswitches are elements present in some mRNAs that form alternative
folded structures depending on the presence or absence of a small
molecule ligand. These alternative structures determine whether
protein is made from the mRNA. Here, a new way by which riboswitches
affect protein expression, by affecting alternative splicing, is
described.
Ming T. Cheah, Andreas Wachter, Narasimhan Sudarsan and Ronald R.
Breaker
10.1038/nature05769
Abstract:
http://www.nature.com/nature/journal/v447/n7143/abs/nature05769.html
Article:
http://www.nature.com/nature/journal/v447/n7143/full/nature05769.html