Darwinismo sistêmico: por que é urgente uma revisão fundamental na Síntese Evolutiva Moderna?

Systemic Darwinism

Rasmus Grønfeldt Winther*

-Author Affiliations

Philosophy Department, University of California, 1156 High Street, Santa Cruz, CA 95064

Edited by Peter Crane, The University of Chicago, Chicago, IL, and approved June 6, 2008 (received for review December 6, 2007)

Abstract

Darwin's 19th century evolutionary theory of descent with modification through natural selection opened up a multidimensional and integrative conceptual space for biology. We explore three dimensions of this space: explanatory pattern, levels of selection, and degree of difference among units of the same type. Each dimension is defined by a respective pair of poles: law and narrative explanation, organismic and hierarchical selection, and variational and essentialist thinking. As a consequence of conceptual debates in the 20th century biological sciences, the poles of each pair came to be seen as mutually exclusive opposites. A significant amount of 21st century research focuses on systems (e.g., genomic, cellular, organismic, and ecological/global). Systemic Darwinism is emerging in this context. It follows a “compositional paradigm” according to which complex systems and their hierarchical networks of parts are the focus of biological investigation. Through the investigation of systems, Systemic Darwinism promises to reintegrate each dimension of Darwin's original logical space. Moreover, this ideally and potentially unified theory of biological ontology coordinates and integrates a plurality of mathematical biological theories (e.g., self-organization/structure, cladistics/history, and evolutionary genetics/function). Integrative Systemic Darwinism requires communal articulation from a plurality of perspectives. Although it is more general than these, it draws on previous advances in Systems Theory, Systems Biology, and Hierarchy Theory. Systemic Darwinism would greatly further bioengineering research and would provide a significantly deeper and more critical understanding of biological reality.

biological theory    ecology   genetics   evolution   systems theory

Footnotes

*E-mail: rgwinther@gmail.com

Author contributions: R.G.W. wrote the paper.

The author declares no conflict of interest.

This article is a PNAS Direct Submission.

© 2008 by The National Academy of Sciences of the USA

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NOTA CAUSTICANTE DESTE BLOGGER:

Em palestras e debates que este blogger tem participado, alguns darwinistas têm a cara de pau de dizer que não existe nenhuma crise epistêmica em biologia evolucionária e, pasme, nenhuma necessidade de uma nova teoria da evolução que não seja selecionista.

Ora, vão caçar sapos de botas epistêmicas na lagoa de Down. Que venga la nueva teoría de evolución – a SÍNTESE EVOLUTIVA AMPLIADA que, por essas e outras montanhas de evidências negativas, não pode e nem deve ser selecionista.


Alô MEC/SEMTEC/PNLEM, que tal recomendar aos autores de livros-texto de Biologia do ensino médio que eles façam a abordagem desta situação epistemológica? Afinal de contas, o fato, Fato, FATO da evolução parece não ser toda esta Coca-Cola toda, oops, assim uma Brastemp no contexto de justificação teórica. Vamos lá gente, honestidade científica acima de tudo, afinal de contas, não existe Theoria perennis em ciência.


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O erro de Darwin - artigo de Marcelo Gleiser

Source/Fonte: New Scientist

SPCNC [Só pra contrariar a Nomenklatura científica]:

Aguardem, brevemente aqui o artigo especial de Marcelo Gleiser sobre o erro de Darwin!!!

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A memória quântica pode derrubar o princípio de incerteza de Heisenberg

Quantum memory may topple Heisenberg's uncertainty principle

By Casey Johnston

Heisenberg meets a qubit.

(If you don't get the joke, this might help)

A quantum memory may be all scientists need to beat the limit of Heisenberg's uncertainty principle, according to a paper published in Nature Physics. According to a group of researchers, maximally entangling a particle with a quantum memory and measuring one of the particle's variables, like its position, should snap the quantum memory in a corresponding state, which could then be measured. This would allow them to do something long thought verboten by the laws of physics: figure out the state of certain pairs of variables at the exact same time with an unprecedented amount of certainty.

Our ability to observe particles at the quantum level is currently limited by Heisenberg's uncertainty principle. Heisenberg noticed that when someone measured one variable of a particle, such as its position, there were some other variables, like momentum, that could not be simultaneously measured with as much precision—there was a small amount of uncertainty applied to one or both of the measurements.

The physical reasoning behind this is hard to follow. But Paul Dirac, another physicist, made up a scenario to illustrate why some variables have this contentious relationship.

Dirac pointed out that one of the only ways to measure a particle's position is by bouncing a photon off of it, and seeing where and how that photon lands on a detector. How the photon lands completely describes the particle's position, but by hitting it, the measurement changes the particle's momentum.

Likewise, a measure of momentum would change the particle's position. Because of this quirk, scientists thought it was impossible to know certain pairs of variables that affect one another at the same exact time with a very high degree of precision.

...

Read more here/Leia mais aqui: ARSTECHNICA

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Nature Physics 

Published online: 25 July 2010 | doi:10.1038/nphys1734

The uncertainty principle in the presence of quantum memory

Mario Berta1,2, Matthias Christandl1,2, Roger Colbeck1,3,4, Joseph M. Renes5 & Renato Renner1

The uncertainty principle, originally formulated by Heisenberg1, clearly illustrates the difference between classical and quantum mechanics. The principle bounds the uncertainties about the outcomes of two incompatible measurements, such as position and momentum, on a particle. It implies that one cannot predict the outcomes for both possible choices of measurement to arbitrary precision, even if information about the preparation of the particle is available in a classical memory. However, if the particle is prepared entangled with a quantum memory, a device that might be available in the not-too-distant future2, it is possible to predict the outcomes for both measurement choices precisely. Here, we extend the uncertainty principle to incorporate this case, providing a lower bound on the uncertainties, which depends on the amount of entanglement between the particle and the quantum memory. We detail the application of our result to witnessing entanglement and to quantum key distribution.

Institute for Theoretical Physics, ETH Zurich, 8093 Zurich, Switzerland

Faculty of Physics, Ludwig-Maximilians-Universität München, 80333 Munich, Germany

Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, Ontario N2L 2Y5, Canada

Institute of Theoretical Computer Science, ETH Zurich, 8092 Zurich, Switzerland

Institute for Applied Physics, Technische Universität Darmstadt, 64289 Darmstadt, Germany

Correspondence to: Roger Colbeck1,3,4 e-mail: rcolbeck@perimeterinstitute.ca

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Einstein estava errado?

Nonstandard Analysis Applied to Special and General Relativity - The Theory of Infinitesimal Light-Clocks

Robert A. Herrmann

(Submitted on 9 Dec 2003 (v1), last revised 22 Aug 2009 (this version, v8))

Nonstandard analysis and electromagnetic propagation properties are used to derive all of the fundamental results for the Special Theory of Relativity. Infinitesimal modeling via infinitesimal light-clocks is used to derive two general line-elements (metrics) without the use of Riemannian geometry. By substituting potential velocities, the Schwarzschild, quasi and modified Schwarzschild, de Sitter, Robertson-Walker and similar line-elements are derived. New black hole and quasi-white hole investigations are presented. A new fixed method using separating operators is used to obtain the major predictions for the relativistic alterations in natural-system behavior. The major conclusion is that all such changes are related to electromagnetic properties and that Riemannian geometry is but an analogue model for natural-system behavior.

Comments: Plain Tex, 109 pages. This monograph has been modified in order to incorporate new research findings

Subjects: General Mathematics (math.GM)

MSC classes: 83A05, 83C99, 03H10

Cite as: arXiv:math/0312189v8 [math.GM]

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Ahmadinejad 'curto e grosso' sobre indulto à adúltera: Lula, por qué no te callas?

03/08/2010 - 06h02

Irã diz que Lula é emotivo e fez proposta de asilo desinformada

da BBC Brasil

O presidente Luiz Inácio Lula da Silva tem uma "personalidade emotiva" e fez sua proposta de conceder asilo à iraniana Sakineh Mohammadi Ashtiani sem "informação suficiente" sobre o caso, segundo afirmou nesta terça-feira o porta-voz do Ministério do Exterior iraniano, Ramin Mehmanparast.

Fonte: The Guardian

Esta foi a primeira reação oficial do Irã à proposta feita no sábado por Lula para que Ashtani, condenada à morte por apedrejamento no Irã sob acusação de adultério, se asile no Brasil.

"O presidente (Lula) da Silva tem uma personalidade muito emotiva e humana, mas provavelmente não tem informação suficiente sobre o caso", declarou o porta-voz.

Mehmanparast disse que a Ashtiani "cometeu um crime" segundo a lei iraniana e que o governo iraniano pode passar mais informações ao presidente Lula "para que ele entenda o caso".

O porta-voz respondia, durante uma entrevista coletiva, à pergunta de um jornalista que havia questionado se havia ou não interferência do presidente brasileiro nessa questão.

A oferta brasileira de asilo a Ashtiani foi feita no fim de semana. O presidente fez um "apelo" ao presidente iraniano, Mahmoud Ahmadinejad, para que "permita ao Brasil conceder asilo a esta mulher", disse Lula, durante um comício em Curitiba.

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Texto integral: Folha de São Paulo/UOL

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NOTA DESTE BLOGGER:

Traduzindo em graúdos, Ahmadinejad mandou um recado 'curto e grosso' para o nosso Grande Timoneiro de Caruaru: "Usted es solamente un inocente útil de la politica nuclear de la ditadura islâmica de Iran. Lula, por qué no te callas? Aqui en Iran quien manda soy yo, oops, os aiatolás."

Traduzindo em miúdos: Lula imagina que tem influência sobre o Irã e outros países, mas esta cornetada do Ahmadinejad vai esfriar o coco, oops a cuca de nosso Grande Timoneiro.

Em 2010, não vote em candidatos antissemitas. E eu não sei por que os presidenciáveis não estão abordando esta questão. Dilma, companheira, você é antissemita???

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Pesquisador condena conformismo entre pares: é coisa de adolescentes!

July 23, 2009, 3:35 PM

Researcher Condemns Conformity Among His Peers

By NICHOLAS WADE

“Academics, like teenagers, sometimes don’t have any sense regarding the degree to which they are conformists.”

So says Thomas Bouchard, the Minnesota psychologist known for his study of twins raised apart, in a retirement interview with Constance Holden in the journal Science.

Journalists, of course, are conformists too. So are most other professions. There’s a powerful human urge to belong inside the group, to think like the majority, to lick the boss’s shoes, and to win the group’s approval by trashing dissenters.

Source/Fonte

The strength of this urge to conform can silence even those who have good reason to think the majority is wrong. You’re an expert because all your peers recognize you as such. But if you start to get too far out of line with what your peers believe, they will look at you askance and start to withdraw the informal title of “expert” they have implicitly bestowed on you. Then you’ll bear the less comfortable label of “maverick,” which is only a few stops short of “scapegoat” or “pariah.”

A remarkable first-hand description of this phenomenon was provided a few months ago by the economist Robert Shiller, co-inventor of the Case-Shiller house price index. Dr. Shiller was concerned about what he saw as an impending house price bubble when he served as an adviser to the Federal Reserve Bank of New York up until 2004.

So why didn’t he burst his lungs warning about the impending collapse of the housing market? “In my position on the panel, I felt the need to use restraint,” he relates. “While I warned about the bubbles I believed were developing in the stock and housing markets, I did so very gently, and felt vulnerable expressing such quirky views. Deviating too far from consensus leaves one feeling potentially ostracized from the group, with the risk that one may be terminated.”

Conformity and group-think are attitudes of particular danger in science, an endeavor that is inherently revolutionary because progress often depends on overturning established wisdom. It’s obvious that least 100 genes must be needed to convert a human or animal cell back to its embryonic state. Or at least it was obvious to almost everyone until Shinya Yamanaka of Kyoto University showed it could be done with just 4.

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Read more here/Leia mais aqui: Tierney Lab - The New York Times

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NOTA IMPERTINENTE DESTE BLOGGER:

Aqui neste blog eu afirmo, ironicamente, que todas as vezes que falarem de consenso científico é melhor procurar por sua carteira epistêmica: ela pode estar sendo tungada pelos agentes da KGB da Nomenklatura científica -- os revisores, peer-reviewers é très chic, chérie, très chic. Agora veio o Thomas Bouchard e diz que consenso é coisa de adolescentes???

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Nanotech: o jogo do lar

Authorized use/Uso autorizado: Nobrow Cartoons

As regras mencionam uma caixa vazia?

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Respeitar o direito dos outros é bom, ou vai ter que aguentar isso: deficiente mental!

SEM COMENTÁRIOS!!!

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TC: Minha irmã 'estrela' Maria das Graças de Almeida Port, Campinas, SP.

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A quinta força física fundamental: um camaleão está conduzindo a dispersão das galáxias?

Is a cosmic chameleon driving galaxies apart?

02 August 2010 by Eugenie Samuel Reich

Magazine issue 2771

A shape-shifting fifth fundamental force could neatly explain the mystery of dark energy – and some other puzzling astronomical observations

ASK A cosmologist for a potted history of the universe, and it might go something like this: the cosmos began some 13.6 billion years ago with a big bang, exploding from a pinprick of searing heat and incredible density. Since then, it has been cooling and expanding: at first exponentially fast, but soon at a more measured, steady tempo.

At that point our friendly cosmologist might give voice to a little embarrassment. Because if measurements of the distance to faraway supernovae are to be believed, around 5 billion years ago the universe's expansion started to accelerate again. We don't know why. A mysterious "dark energy" permeating space is generally fingered as the culprit. But while this entity apparently flings galaxies apart with gusto, it has never been seen or produced in the lab and seemingly does not interact directly with light or matter on Earth or elsewhere. Such undetectability runs counter to the stuff of science.

Or are we just overlooking evidence that is already there? Some inconsistencies in recent astrophysical observations, easy to dismiss as blips if taken on their own, might invite a startling conclusion when looked at together: that the cosmos is suffused by a fifth force in addition to the canonical four of gravity, electromagnetism and the strong and weak nuclear forces. What is unusual about this force is that its range changes according to its environment - a cosmic chameleon that might just explain the mysteries of dark energy.

The basic idea for this fifth force was hatched in 2004 by Justin Khoury and Amanda Weltman, then members of a team led by well-known string theorist Brian Greene at Columbia University in New York City. String theory is the favoured route to unifying gravity, the odd one out among the four forces, with the other three under the umbrella of quantum mechanics. It is a great playground for devising new fields and forces. The theory is formulated in 11 dimensions, seven of which are assumed to be curled up so small that we cannot see them. Disturbances in those curled-up dimensions might make themselves felt as "extra" forces in the four dimensions of space and time we do see.

For this picture to make sense, the effects in the visible dimensions must match our observations of the universe. Khoury and Weltman proposed one way of doing this: an extra force could be transmitted by particles whose mass depends on the density of the matter around them. That way, its effects could remained veiled on Earth.

How would that work? Well, in quantum mechanics, the range of influence of a force depends largely on the mass of the particles produced by the associated force field: the lighter the particle, the longer the force's range. Electromagnetic fields, for example, produce photons that have no mass whatsoever, so the range of the electromagnetic force is infinite. The particles that transmit the weak nuclear force, on the other hand, are extremely heavy and do not travel very far, confining the force to the tiny scales of the atomic nucleus. With the strong nuclear force, things are slightly more complex: the associated particles, called gluons, are massless but also have the ability to interact with themselves, preventing the force from operating over large distances.

Khoury and Weltman started from the observation that the average density of matter in Earth's vicinity is very high in cosmic terms, at about 0.5 grams per cubic centimetre. Under these circumstances, they proposed, the particle that transmits the chameleon force would be about a billion times lighter than the electron. The force itself would then have a range of not more than a millimetre - small enough for its effects to have remained undetected in the lab so far.

In the wide open spaces of the cosmos, however, where a cubic centimetre contains just 10-29 grams of matter on average, the mass of the chameleon particle plummets by something like 22 orders of magnitude, producing a muscular force that could act over millions of light years. The lost mass is picked up as energy by the chameleon field.

Although the initial motivation was not to find a mechanism to explain dark energy, the idea that the chameleon might do so was always on their minds, says Weltman. With a few tweaks, it did. It could be made to create a kind of negative pressure that, on cosmic scales, would produce a repulsive effect in opposition to gravity. And with its dependence on density, the chameleon force could be made to appear 5 billion years ago, when the density of the expanding cosmos fell below a critical value. The force would propel galaxies away from one another at an ever-increasing rate, producing the kind of accelerated expansion we observe in the wider cosmos, all the while remaining hidden on Earth.

...

Read more here/Leia mais aqui: New Scientist

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Regulação transcricional pela proteína P53

Transcriptional Regulation by P53

Rachel Beckerman and Carol Prives

-
Author Affiliations

Department of Biological Sciences, Columbia University, New York, New York 10027

Correspondence:clp3@columbia.edu

Abstract

Inactivation of p53 is critical for the formation of most tumors. Illumination of the key function(s) of p53 protein in protecting cells from becoming cancerous is therefore a worthy goal. Arguably p53’s most important function is to act as a transcription factor that directly regulates perhaps several hundred of the cell’s RNA polymerase II (RNAP II)-transcribed genes, and indirectly regulates thousands of others. Indeed p53 is the most well studied mammalian transcription factor. The p53 tetramer binds to its response element where it can recruit diverse transcriptional coregulators such as histone modifying enzymes, chromatin remodeling factors, subunits of the mediator complex, and components of general transcription machinery and preinitiation complex (PIC) to modulate RNAPII activity at target loci (Laptenko and Prives 2006). The p53 transcriptional program is regulated in a stimulus-specific fashion (Murray-Zmijewski et al. 2008; Vousden and Prives 2009), whereby distinct subsets of p53 target genes are induced in response to different p53-activating agents, likely allowing cells to tailor their response to different types of stress. How p53 is able to discriminate between these different loci is the subject of intense research. Here, we describe key aspects of the fundamentals of p53-mediated transcriptional regulation and target gene promoter selectivity.

Copyright © 2010 Cold Spring Harbor Laboratory Press; all rights reserve

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Organização de alta ordem do genoma em doença humana

Higher-order Genome Organization in Human Disease

Tom Misteli

-Author Affiliations

National Cancer Institute, NIH, Bethesda, Maryland 20892

Correspondence:mistelit@mail.nih.gov

Abstract

Genomes are organized into complex higher-order structures by folding of the DNA into chromatin fibers, chromosome domains, and ultimately chromosomes. The higher-order organization of genomes is functionally important for gene regulation and control of gene expression programs. Defects in how chromatin is globally organized are relevant for physiological and pathological processes. Mutations and transcriptional misregulation of several global genome organizers are linked to human diseases and global alterations in chromatin structure are emerging as key players in maintenance of genome stability, aging, and the formation of cancer translocations.

Copyright © 2010 Cold Spring Harbor Laboratory Press; all rights reserved

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Transporte de membrana em células primitivas

Membrane Transport in Primitive Cells

Sheref S. Mansy

-Author Affiliations

Armenise-Harvard Laboratory of Synthetic and Reconstructive Biology, Centre for Integrative Biology (CIBIO), University of Trento, Italy

Correspondence:mansy@science.unitn.it

Abstract

Although model protocellular membranes consisting of monoacyl lipids are similar to membranes composed of contemporary diacyl lipids, they differ in at least one important aspect. Model protocellular membranes allow for the passage of polar solutes and thus can potentially support cell-to functions without the aid of transport machinery. The ability to transport polar molecules likely stems from increased lipid dynamics. Selectively permeable vesicle membranes composed of monoacyl lipids allow for many lifelike processes to emerge from a remarkably small set of molecules.

Copyright © 2010 Cold Spring Harbor Laboratory Press; all rights reserved

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O núcleo florescente de levedura

The Budding Yeast Nucleus

Angela Taddei1,2, Heiko Schober3 and 

Susan M. Gasser3

-Author Affiliations

1UMR 218, Centre National de la Recherche Scientifique, 26 rue d'Ulm, 75231 Paris Cedex 05, France

2Institut Curie-Section de Recherche, 26 rue d'Ulm, 75231 Paris Cedex 05, France

3Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland

Correspondence:susan.gasser@fmi.ch

Abstract

The budding yeast nucleus, like those of other eukaryotic species, is highly organized with respect to both chromosomal sequences and enzymatic activities. At the nuclear periphery interactions of nuclear pores with chromatin, mRNA, and transport factors promote efficient gene expression, whereas centromeres, telomeres, and silent chromatin are clustered and anchored away from pores. Internal nuclear organization appears to be function-dependent, reflecting localized sites for tRNA transcription, rDNA transcription, ribosome assembly, and DNA repair. Recent advances have identified new proteins involved in the positioning of chromatin and have allowed testing of the functional role of higher-order chromatin organization. The unequal distribution of silent information regulatory factors and histone modifying enzymes, which arises in part from the juxtaposition of telomeric repeats, has been shown to influence chromatin-mediated transcriptional repression. Other localization events suppress unwanted recombination. These findings highlight the contribution budding yeast genetics and cytology have made to dissecting the functional role of nuclear structure.

Copyright © 2010 Cold Spring Harbor Laboratory Press; all rights reserved

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In vivo RNAi: hoje e amanhã

In vivo RNAi: Today and Tomorrow 

1. Norbert Perrimon1,2, 

2. Jian-Quan Ni1,2 and 

3. Lizabeth Perkins3 

-Author Affiliations 

1. 1Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115 

2. 2Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts 02175 

3. 3Pediatric Surgical Research Labs, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114 

1. Correspondence:perrimon@receptor.med.harvard.edu 

SUMMARY 

RNA interference (RNAi) provides a powerful reverse genetics approach to analyze gene functions both in tissue culture and in vivo. Because of its widespread applicability and effectiveness it has become an essential part of the tool box kits of model organisms such as Caenorhabditis elegans, Drosophila, and the mouse. In addition, the use of RNAi in animals in which genetic tools are either poorly developed or nonexistent enables a myriad of fundamental questions to be asked. Here, we review the methods and applications of in vivo RNAi to characterize gene functions in model organisms and discuss their impact to the study of developmental as well as evolutionary questions. Further, we discuss the applications of RNAi technologies to crop improvement, pest control and RNAi therapeutics, thus providing an appreciation of the potential for phenomenal applications of RNAi to agriculture and medicine. 

Copyright © 2010 Cold Spring Harbor Laboratory Press; all rights reserved

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Cientistas brasileiros descobrem o 'guardião' do genoma: proteína ajuda controlar o DNA danificado de leveduras

'Guardian of the Genome': Protein Helps Prevent Damaged DNA in Yeast

ScienceDaily (Aug. 1, 2010) — Like a scout that runs ahead to spot signs of damage or danger, a protein in yeast safeguards the yeast cells' genome during replication -- a process vulnerable to errors when DNA is copied -- according to new Cornell research.

Researchers from Cornell University's Weill Institute for Cell and Molecular Biology have discovered how a protein called Mec1 plays the role of "guardian of the genome," explained Marcus Smolka, assistant professor of molecular biology and genetics. The findings are detailed in the journal Molecular Cell.

Previous studies have shown that cells lacking Mec1 accumulate damaged DNA and become more sensitive to agents that interfere with replication. The researchers report that the Mec1 protein monitors and repairs the machinery responsible for replicating the DNA. At times, when DNA becomes damaged, the replication machinery can actually detach from the DNA -- like a train coming off a track -- but Mec1 coordinates the repair of the machinery and the DNA itself, allowing it to restart and continue replicating.

"Mec1 organizes the cell's response against things that jeopardize the integrity of the genome," Smolka said.

During the replication process, Mec1 accumulates at trouble spots such as lesions in the DNA or other blocks to replication. Mec1 is known as a kinase, a type of enzyme that modifies other proteins by adding a phosphate group to them (a process called phosphorylation), which then leads to a functional change in the protein. The researchers report that Mec1 adds a phosphate group to a protein known as Slx4, which then triggers Slx4 to anchor to the replication machinery. Slx4 then can employ a variety of tools to repair DNA and the replication machinery.

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Read more here/Leia mais aqui: Science Daily

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Molecular Cell, Volume 39, Issue 2, 300-306, 30 July 2010

doi:10.1016/j.molcel.2010.06.019

DNA Damage Signaling Recruits the Rtt107-Slx4 Scaffolds via Dpb11 to Mediate Replication Stress Response

Patrice Y. Ohouo1, 2, 3, Francisco M. Bastos de Oliveira2, 3, Beatriz S. Almeida2 and Marcus B. Smolka2, , 

1 Graduate Program in Biochemistry, Molecular and Cell Biology, Weill Institute for Cell and Molecular Biology, Cornell University, 339 Weill Hall, Ithaca, New York 14853-7202, USA

2 Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, 339 Weill Hall, Ithaca, New York 14853-7202, USA

Corresponding author

³ These authors contributed equally to this work

• 
  

  Highlights

► Mec1 mediates interaction between Dpb11 and the Rtt107-Slx4 scaffolds ► Mutation of canonical Mec1 phosphosites in Slx4 disrupts its interaction with Dpb11 ► Disruption of Dpb11-Slx4 interaction results in sensitivity to replication stress
• 
  
  

  Summary

• The DNA damage checkpoint kinase Mec1^ATR is critical for maintaining the integrity of replication forks. Though it has been proposed to promote fork repair, the mechanisms by which Mec1 regulates DNA repair factors remain unclear. Here, we found that Mec1 mediates a key interaction between the fork protein Dpb11 and the DNA repair scaffolds Slx4-Rtt107 to regulate replication stress response. Dissection of the molecular basis of the interaction reveals that Slx4 and Rtt107 jointly bind Dpb11 and that Slx4 phosphorylation is required. Mutation of Mec1 phosphorylation sites in Slx4 disrupts its interaction with Dpb11 and compromises the cellular response to replisomes blocked by DNA alkylation. Multiple fork repair factors associate with Rtt107 or Slx4, supporting that Mec1-dependent assembly of the Rtt107-Slx4-Dpb11 complex functions to coordinate fork repair. Our results unveil how Mec1 regulates the Slx4 and Rtt107 scaffolds and establish a mechanistic link between DNA damage signaling and fork repair.
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Palavras salientadas em vermelho para destacar a linguagem teleológica do abstract. Os autores da pesquisa não são proponentes do Design Inteligente: são as evidências encontradas na natureza que revelam teleologia, e os cientistas não puderam dizer o contrário.

Design inteligente ou mero acaso, fortuita necessidade via seleção natural y otros mecanismos evolutivos ao longo das eras???

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Professores, pesquisadores e alunos de universidades públicas e privadas com acesso ao site CAPES/Periódicos podem ler gratuitamente este artigo da Molecular Cell e de mais 22.440 publicações científicas.

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Os brasileiros são Francisco M. Bastos de Oliveira, Beatriz S. Almeida e Marcus B. Smolka. O Dr. Marcus B. Smolka dirige o Laboratory of Proteomics and Cell Signaling na Cornell University. Smolka recebeu apoio financeiro da FAPESP na sua formação acadêmica e fez parte da equipe do Prof. Dr. José Camillo Novello, da Unicamp, que trabalhou com o produto dos genes, as proteínas.

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Atacar com mísseis: não tem importância nenhuma

Authorized use/Uso autorizado: Yaakov Kirschen Dry Bones Blog

1. Gaza está lançando mísseis novamente...

2. em cidades e vilas israelenses...

3. mas isso não tem nenhuma importância.

4. Não tem importância nenhuma?

    Nananina, não.

5. E não vai ter importância nenhuma...

6. até Israel retaliar.

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Para, por e com Israel, sempre!

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