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# r3 @2 o) M3 T/ {8 N8 q7 W8 ^) oARTICLES
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/ M! z3 [' f. t6 U tLight-avoidance-mediating photoreceptors tile the Drosophila larval
& O& r7 n; w- W& Abody wall pp921 - 926+ F0 Q9 s( } X' o
Light sensing outside the eyes is common in many animals but is
3 N( s1 l$ O, F9 c @) R( Yusually confined to specialized organs. Here, the entire body wall of % g2 L$ \ A }. r; x) U
the fruitfly larva is found to be tiled with blue- and ultraviolet-
& P- T6 o: X1 d; A# \( Nlight sensing neuronal dendrites, which are essential for the larva's % V9 _: ~5 R! C4 \ T/ P$ J1 e# J
innate light-avoidance behaviour. The phototransduction machinery used 3 S2 `, T1 j9 |2 U7 H6 i3 L
by these neurons is distinct from other Drosophila photoreceptor
: h5 }1 Z7 l+ _, Imolecules but similar to a system recently identified in nematode 5 a, R9 n# Q& {! a5 |% K7 ~; |2 G
neurons., ^4 c3 f+ o. e1 q/ \
Yang Xiang et al.5 u* Q. ^2 O0 y7 u- F- p7 p8 G
doi:10.1038/nature09576
0 {2 C; w6 K r! K: B: P1 l& E @Abstract: http://www.nature.com/nature/jou ... bs/nature09576.html3 J0 H% U" K; k' h: L2 ]
Article: http://www.nature.com/nature/jou ... ll/nature09576.html3 q5 I: Z5 [3 o0 M- S
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TRIM24 links a non-canonical histone signature to breast cancer pp927 7 ]5 S; D d M, @* ^
- 932
0 ~1 g( F$ Q8 z5 oA crystal structure of the tandem PHD and bromodomain regions of the
* K! m& c* h$ x, Ftranscription and chromatin regulator TRIM24 reveals combinatorial + G" [% _5 L6 T: B' P& A" Z1 N
recognition of dual marks on the histone H3 tail. TRIM24 is involved ) j- L" Z( A: ]3 u* |
in activation of oestrogen-dependent genes and is aberrantly expressed $ B0 J% u3 t, }
in breast cancer.
( K0 Q, I' c, L7 P) e3 E, |. IWen-Wei Tsai et al.
7 f1 P4 U( X$ I: d Vdoi:10.1038/nature09542- L) n, `4 @! O( i
Abstract: http://www.nature.com/nature/jou ... bs/nature09542.html
z# |; Q/ }& o4 WArticle: http://www.nature.com/nature/jou ... ll/nature09542.html3 _; _2 w- w/ W: {
' t' A1 L& x* |* oCRTC3 links catecholamine signalling to energy balance pp933 - 939. l9 u& C# @2 A
β-adrenergic receptor signalling in adipocytes stimulates energy
9 L# F0 i. v) a) D# H; ], bexpenditure via cAMP-dependent increases in lipolysis and fatty-acid ' V( `4 Q8 m" I# G- y7 e' y
oxidation, and this signalling mechanism is thought to be disrupted in $ f. z$ X; ]1 L# m H$ j
obesity. Here, the cAMP-responsive CREB coactivator Crtc3 is shown to & Y$ W5 ^6 _) m6 z$ `- t
promote obesity in mice by attenuating β adrenergic receptor
+ N7 ~1 s5 ?% ^3 ~6 ^3 V" {% Ssignalling in adipose tissue.
3 m+ G) g0 a. {( Q4 T! x8 ~) t# p, AYoungsup Song et al.2 S9 Q/ X$ \: [! j. K; c
doi:10.1038/nature09564! |2 z4 P: Y( [7 Y/ @: |
Abstract: http://www.nature.com/nature/jou ... bs/nature09564.html, W+ J; `8 d1 O3 i# A7 `
Article: http://www.nature.com/nature/jou ... ll/nature09564.html# c+ l% U- b9 d% Y
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LETTERS
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* k. w0 p; z, O1 G4 U4 TA substantial population of low-mass stars in luminous elliptical
. V, O2 a" v% Z) rgalaxies pp940 - 942
! v ~- R; y6 b1 d5 i6 CThe stellar initial mass function describes the mass distribution of , K6 J" e5 S3 l/ d/ R, y5 G
stars at the time of their formation. This study reports observations
% `! f0 j: c, x+ s7 q. O$ d7 a7 ]of the Na I doublet and the Wing-Ford molecular FeH band in the ' D- ^ z/ ], W$ b% b- J
spectra of elliptical galaxies. These lines are strong in stars with 1 U; W* a D) h" K: e1 @
masses
& I% _0 x$ C% b9 l2 u$ h4 @6 ?- K2 MPieter G. van Dokkum and Charlie Conroy+ g3 N; Z& u0 `' U* X
doi:10.1038/nature09578# \# S0 E8 t* M
Abstract: http://www.nature.com/nature/jou ... bs/nature09578.html% @: I: X3 ~' K$ |
Article: http://www.nature.com/nature/jou ... ll/nature09578.html
/ f" t* M, Q9 T/ y! M. Y' `3 R* |; g5 D5 n. q! M Y
Origin of Saturn’s rings and inner moons by mass removal from a lost 9 g# Q: ?) @/ ^, F2 M/ N
Titan-sized satellite p943
0 y" i4 ^+ o1 T5 b2 VSaturn's rings are more than 90–95% water ice, which implies that
, Y4 a) y8 u5 j! Yinitially they were almost pure ice because they are continually ' W" t9 E! g4 x6 _
polluted by rocky meteoroids. Saturn has only one large satellite, : ~7 n, c3 x$ {
Titan, whereas Jupiter has four large satellites; additional large
) ? c) ~& V8 J( Bsatellites probably existed originally but were lost as they spiralled $ @9 ]6 J* I) T; f" e; O, Z
into Saturn. Now, numerical simulations of the tidal removal of mass - g7 D5 {) T4 \+ q0 n, J. e: T( d
from a differentiated, Titan sized satellite as it migrates inward
. S' B, u# W4 Z( Xtowards Saturn are reported. Planetary tidal forces preferentially
! f3 [1 u8 N, {' |8 U6 w" f6 L9 bstrip material from the satellite's outer icy layers, while its rocky 1 Y7 Y P$ u. d$ R
core remains intact and is lost to collision with the planet. The ( U: [! |& X* @1 v
result is a pure ice ring.
- v! [8 d( w5 Q+ e! DRobin M. Canup& j# ]4 W$ o7 j2 o2 y- D' ~
doi:10.1038/nature09661
/ `7 f* n" k$ u9 L% HAbstract: http://www.nature.com/nature/jou ... bs/nature09661.html
* M% r4 G D. t8 g/ P$ sArticle: http://www.nature.com/nature/jou ... ll/nature09661.html
* E2 y/ ?& m o5 w# ` s6 A D" F! W: }0 n$ h: R+ }
Pleats in crystals on curved surfaces pp947 - 951. }/ D6 G4 i7 c5 [) X6 X2 t
Hexagons can easily tile a flat surface, but not a curved one. Defects
# [% O6 O( K8 f6 z" H/ n% F, Y9 xwith topological charge (such as heptagons and pentagons) make it 2 U% w" P) _8 x1 ?6 Q! \2 \8 Y
easier to tile curved surfaces, such as soccer balls. Here, a new type
. q/ |& @( O/ h8 K4 n% cof defect is reported that accommodates curvature in the same way as . d$ V% L1 @+ V; {5 D: c' {
fabric pleats. The appearance of such defects on the negatively curved
7 ~5 Y6 B- O4 ]" ~surfaces of stretched colloidal crystals are observed. The results
1 V2 g# ] k3 B" ~: x _will facilitate the exploration of general theories of defects in , d% ]6 s; t: |6 W
curved spaces, the engineering of curved structures and novel methods
( X: x8 b9 A( Y3 F. efor soft lithography and directed self-assembly.
; j* w8 q+ W) I; }7 ?; oWilliam T. M. Irvine, Vincenzo Vitelli and Paul M. Chaikin+ H$ \% ]8 n; m( v9 G" @) x
doi:10.1038/nature09620
, f; X" _: J& [2 kAbstract: http://www.nature.com/nature/jou ... bs/nature09620.html4 ^2 E# M9 T( V$ l
Article: http://www.nature.com/nature/jou ... ll/nature09620.html
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Tidal dissipation and the strength of the Earth’s internal magnetic
5 J! n) l- [ ]7 N; pfield pp952 - 954
' X' u' Z/ f0 \6 C, v6 pHere, an indirect estimate for the magnetic field strength within the
; P8 m0 N3 K5 q- z+ d1 ~Earth's core from measurements of tidal dissipation is presented.
4 ^" U. e# l9 G) \. q. k# RPreviously reported evidence of anomalous dissipation in the Earth's ( {& B) \2 j1 w3 u& s# I' ^/ D
nutations can be explained with a core-averaged field of 2.5 mT,
, g: H/ w, g9 s% leliminating the need for high fluid viscosity or a stronger magnetic
# p! w* M) E2 ~4 O! |field at the inner-core boundary.: l# W9 P l9 H. y7 K, B+ @3 y# k
Bruce A. Buffett5 N4 `8 J: |$ G/ L& A- { ^/ b% j
doi:10.1038/nature09643: z8 Z7 N# u- c. Z8 E, R* B. f# _0 M
Abstract: http://www.nature.com/nature/jou ... bs/nature09643.html
. [9 t2 A% X HArticle: http://www.nature.com/nature/jou ... ll/nature09643.html1 ?1 @4 V$ j8 D. _
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Greenhouse gas mitigation can reduce sea-ice loss and increase polar : x8 c+ g8 d- @: r' q5 N. k m% S9 U
bear persistence pp955 - 958
0 H3 B' B9 @9 \! s0 HThe dramatic loss of Arctic sea ice with climate change has led to the
4 a. d S; X# O% R: Rprediction of a tipping point beyond which ice loss is irreversible ! n3 X+ `) @& `. k
and polar bear habitat will be catastrophically lost. By contrast, % |8 v% o+ K$ ?, }
this study shows a linear relationship between temperature and sea-ice
9 O9 h+ A: ]) o$ b" V9 pcoverage that overcomes the albedo effect that would cause a tipping
1 m( o7 Y5 g8 cpoint. As a result, reducing greenhouse gas emissions can have a 1 x4 M# F! q6 D
positive effect on polar bear populations.6 I! V( e3 P u& B+ g' [
Steven C. Amstrup et al.
7 I( S$ _6 \- N! P" _* udoi:10.1038/nature09653
$ \" x4 c: [* y( ^1 L7 a( k1 d% B1 P# cAbstract: http://www.nature.com/nature/jou ... bs/nature09653.html
6 N) _: |* z5 t( E9 lArticle: http://www.nature.com/nature/jou ... ll/nature09653.html( C3 T. ~: f& f! w1 O5 o b
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Intercalation of a new tier of transcription regulation into an
+ |! l5 |( V) M0 G( ~ _0 Tancient circuit pp959 - 963
* ~) }1 q7 a& W$ uHow new phenotypes can be introduced during evolution without losses " z7 \5 [ V* U* k; E& c5 R# J8 H
of fitness remains largely unexplained at the molecular level. By 1 X& J4 z! l( a" o% ]+ ?' j" r
comparing the molecular details of a well known process — mating type : R8 H% x% Y \: ~+ P
determination — across a large diversity of yeast species, the
9 ^0 S- g4 u( r6 c. I; enetwork rewiring event of the intercalation of a new level of gene , C8 v% [8 \0 } H# K
transcription control into an ancient regulatory circuit is shown, : |9 @! _1 R+ V6 L) d. O
which allowed for the creation of a new phenotype — taking food
$ D+ P3 e! `3 b& oavailability into account when deciding to mate.
$ A; \" M# k9 S6 ELauren N. Booth, Brian B. Tuch and Alexander D. Johnson P4 r! A: y9 d: F- B, a2 L2 }
doi:10.1038/nature09560
6 C+ U9 T) Z- VAbstract: http://www.nature.com/nature/jou ... bs/nature09560.html1 R6 u" ]3 z, t+ l
Article: http://www.nature.com/nature/jou ... ll/nature09560.html. q" k7 H6 ]3 T& O# q2 d& w; i
( I2 _, T4 F5 k7 F% w- A7 _/ h3 CNoise correlations improve response fidelity and stimulus encoding / C8 M) U2 [! u
pp964 - 9671 {$ ~( A* B' k! \# |4 n" K
This study introduces a novel recording technique for simultaneously % V5 y6 [ ], m
measuring excitatory and inhibitory conductances of retinal ganglion " V: R5 Q7 G& W6 k1 a# I. D
cells to show that excitatory and inhibitory inputs are strongly " g1 J `: s" P
correlated, thereby cancelling each other. Furthermore, dynamic clamp 2 |( O8 v+ @5 _; Q' C) S. P# \; G
is used to introduce these conductance changes into the cell with or ( a; w* i6 o' x
without correlations, and it is found that, as predicted by 7 i9 ] y+ p: p# a' v0 m* c3 f
theoretical work, correlations significantly increase reliability of 8 Q2 v% F9 }3 G6 ~# L G a
the spiking response.# D7 O2 B! N4 ~1 Q7 ^# E
Jon Cafaro and Fred Rieke; i7 @4 D+ W4 n, K2 D. d5 f
doi:10.1038/nature09570! p* I( }/ p% E
Abstract: http://www.nature.com/nature/jou ... bs/nature09570.html
% ~8 q( z z8 l- W* mArticle: http://www.nature.com/nature/jou ... ll/nature09570.html9 G/ g6 c' _1 n7 Q, f
* K% e4 T! Z7 g, _6 ]
COT drives resistance to RAF inhibition through MAP kinase pathway
) O- X% a# |- S, H0 g& Y; f# ~reactivation pp968 - 9729 Z4 ?1 R. r: I
Recent data from early clinical trials in melanoma patients carrying
. g0 T2 a, z O0 r1 d. A/ \% H, M' }mutations in the B-RAF gene have shown promising results with the B- 8 j9 I K8 B8 H% ]5 n
RAF kinase inhibitor PLX4032; however, many patients eventually 1 ]) m1 Z6 s; L8 {2 D
develop resistance to this treatment. Two papers now uncover possible
" \. p1 @% g+ I5 m+ c! |) `mechanisms of resistance to PLX4032. One paper shows that upregulation " \- N9 ]0 `* R& g- F
of MAP3K8 (which encodes COT) can confer resistance of melanoma cells / b0 m1 D7 [, f, e# r
to B-RAF inhibitors, whereas another paper found that melanomas can E; t) _& Q" C" D7 \# R
acquire resistance due to mutations of N-RAS or increased expression
8 o# o' _( Z0 D* T" Gof PDGFRβ. Each of these resistance mechanisms seems to apply to at
" Y/ Q* p0 X" Zleast some patients on recent PLX4032 trial, whereas, surprisingly, so 4 X5 q! J* [; F, n( d$ I
far no secondary B-RAF mutations have been observed.
1 Z* d( t9 z( O4 p, G2 @Cory M. Johannessen et al.
v; R' a2 p _" ~% Jdoi:10.1038/nature09627& D- R* f* t3 M1 I$ c8 ~$ C
Abstract: http://www.nature.com/nature/jou ... bs/nature09627.html3 h' y) P+ {' U J- d* J1 Z9 B& R
Article: http://www.nature.com/nature/jou ... ll/nature09627.html
4 l$ y( [0 O+ f$ x9 u! k+ s7 O6 V9 w
. G$ Q: t- x# z- U# x4 [Melanomas acquire resistance to B-RAF(V600E) inhibition by RTK or N- ; v- `' x( s4 j9 a! E6 R; o# B
RAS upregulation pp973 - 977
1 s6 T2 ]9 k) X8 m$ X, D* A; h; Y8 hRecent data from early clinical trials in melanoma patients carrying
# A/ c$ O: }: n4 {, d+ B* p1 s2 ^mutations in the B-RAF gene have shown promising results with the B-
# P/ g5 q1 M: \3 p. iRAF kinase inhibitor PLX4032; however, many patients eventually
$ y; i6 Q: E8 ~: Hdevelop resistance to this treatment. Two papers now uncover possible - |1 w z8 O$ R$ z/ z* y
mechanisms of resistance to PLX4032. One paper shows that upregulation
) B$ E- V& h, r6 n# Nof MAP3K8 (which encodes COT) can confer resistance of melanoma cells
M% t7 R! c9 p; F2 U) z& z- Jto B-RAF inhibitors, whereas another paper found that melanomas can
/ M* g& P% m! K* C# g. O$ `acquire resistance due to mutations of N-RAS or increased expression , n5 E0 h( j7 l7 p! u
of PDGFRβ. Each of these resistance mechanisms seems to apply to at
2 s; ]1 S$ @2 i( ~0 m5 z# [+ ]+ N6 Ileast some patients on recent PLX4032 trial, whereas, surprisingly, so 3 {) @! Y% S; [" |6 F
far no secondary B-RAF mutations have been observed.! Y$ d" ]; z) R6 V, F
Ramin Nazarian et al.
$ H6 f) ~: m/ R }: qdoi:10.1038/nature09626
/ g$ D6 f3 O/ z R0 L" `! j3 YAbstract: http://www.nature.com/nature/jou ... bs/nature09626.html& x k$ M. u9 X8 g7 }" ~
Article: http://www.nature.com/nature/jou ... ll/nature09626.html! f$ d& i I1 e5 Z4 a& x# p
7 E2 P9 L+ t# h$ W* s+ {
Crystal structure of bacterial RNA polymerase bound with a
& I0 E. U- S+ Z6 J; ftranscription inhibitor protein pp978 - 9822 Q4 v# N/ ~. G/ x. R
A crystal structure of bacterial RNA polymerase (RNAP) bound to the 6 @% G$ A N: r+ O: b
transcription inhibitor Gfh1 reveals the mechanism of inhibition by
2 w, v- n8 k3 {5 TGfh1 and an alternative ratcheted state of RNAP.
! L, K3 i1 k# Z- VShunsuke Tagami et al.
/ v/ ]1 O6 w3 S8 t Z d/ Xdoi:10.1038/nature09573: G0 a1 Z; {# K" C% f
Abstract: http://www.nature.com/nature/jou ... bs/nature09573.html
. C2 T/ `9 r eArticle: http://www.nature.com/nature/jou ... ll/nature09573.html- V+ k. G* M5 H! g
& \- r1 V& y) C6 W
Single-molecule imaging reveals mechanisms of protein disruption by a
, Y9 V# w1 K$ \+ l' C0 P2 c0 aDNA translocase pp983 - 987, D0 a: z' ^9 p: M
Protein machineries that move along the DNA, such as DNA polymerases
+ @8 n8 y6 L% M/ C9 Wand helicases, will necessarily encounter other bound proteins / n) n$ K' f, s/ v
interacting with specific sites. Using 'curtains' of labelled DNA,
- O6 d& t6 m6 [3 F9 l) Dthis study measured whether such bound proteins interfere with the ; \/ \ v3 i2 R1 L
activity of the bacterial DNA translocase RecBCD. The translocase is 2 ]9 |$ J! y+ m4 l1 r7 I
able to push the proteins over nonspecific sites for thousands of base 3 K$ N }2 a4 ~+ J- l
pairs before they are displaced.# ` u/ `# a$ n* Z
Ilya J. Finkelstein, Mari-Liis Visnapuu and Eric C. Greene7 D/ h% _ F4 M# S
doi:10.1038/nature09561
+ I3 H c4 Q$ o' t% @0 y2 AAbstract: http://www.nature.com/nature/jou ... bs/nature09561.html: e9 a+ C" s/ i: m7 H
Article: http://www.nature.com/nature/jou ... ll/nature09561.html
+ h1 n" I6 s0 a8 `# @3 |5 U" C8 j/ V \
The mechanism of sodium and substrate release from the binding pocket ; M* M# q' N: ^8 ~# ^+ k
of vSGLT pp988 - 991
U B5 q4 d) G" k8 y6 W; @! _5 G. xHere, a comprehensive study of the sodium/galactose transporter 1 q; ]) o) _' z$ @% [8 ~
(vSGLT) is presented, consisting of molecular dynamics simulations,
9 \6 V, Y2 j R! `, G' Sbiochemical characterization and a new crystal structure of the ! k) _ H c, i' N. q
'inward-open' conformation. These experiments show that sodium exit
9 } d9 d( R+ R0 g; D; |causes a reorientation of transmembrane helix 1, opening an inner gate 0 s: x3 M7 `! Z P
required for substrate exit, while also triggering minor rigid-body ; ?4 h$ L9 E1 s& x2 B+ @" x
movements in two sets of transmembrane helical bundles. This cascade
9 \6 n4 o8 l. W/ c4 rof conformational changes is responsible for the proper timing of ion ( w, Q, r7 k$ g6 H6 u4 b4 s
and substrate release. |
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发表于 2010-12-16 16:18
非常好 谢谢楼主
发表于 2010-12-17 10:30
