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At Quanta: Cells find “optimal” solutions, not just good ones

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structure of an animal cell/royroydeb (CC BY-SA 4.0)

We are told that cells’s ability hints at “a more general principle of life”:

The same precision and reproducibility emerge from a sea of noise again and again in a range of cellular processes. That mounting evidence is leading some biologists to a bold hypothesis: that where information is concerned, cells might often find solutions to life’s challenges that are not just good but optimal — that cells extract as much useful information from their complex surroundings as is theoretically possible. Questions about optimal decoding, according to Aleksandra Walczak, a biophysicist at the École Normale Supérieure in Paris, “are everywhere in biology.”Jordana Cepelewicz, “The Math That Tells Cells What They Are” at Quanta

What then becomes of “bad design” arguments, like those of Nathan Lents? In a transient world, any solution can only be optimal for a given life, as it must be factored against other lives.

Before you go: In Nature: Cells have “secret conversations” We say this a lot: That’s a lot of information to have simply come into being by natural selection acting on random mutation (Darwinism). It’s getting not only ridiculous but obviously ridiculous.

Researchers: Helpful gut microbes send messages to their hosts If the strategy is clearly identified, they should look for non-helpful microbes that have found a way to copy it (horizontal gene transfer?)

Cells and proteins use sugars to talk to one another Cells are like Neanderthal man. They get smarter every time we run into them. And just think, it all just tumbled into existence by natural selection acting on random mutations (Darwinism) too…

Researchers: First animal cell was not simple; it could “transdifferentiate” From the paper: “… these analyses offer no support for the homology of sponge choanocytes and choanoflagellates, nor for the view that the first multicellular animals were simple balls of cells with limited capacity to differentiate.”

“Interspecies communication” strategy between gut bacteria and mammalian hosts’ genes described

Researchers: Cells Have A Repair Crew That Fixes Local Leaks

Researchers: How The Immune System “Thinks”

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Researcher: Mathematics Sheds Light On “Unfathomably Complex” Cellular Thinking

How do cells in the body know where they are supposed to be?

Researchers A Kill Cancer Code Is Embedded in Every Cell

Comments
Central dogma rates and the trade-off between precision and economy in gene expression. 2019 NATURE COMMUNICATIONS Volume: 10, Issue: 1, pp 68-68 Jean Hausser, Avi Mayo, Leeat Keren, Uri Alon Weizmann Institute of Science
Steady-state protein abundance is set by four rates: transcription, translation, mRNA decay and protein decay. A given protein abundance can be obtained from infinitely many combinations of these rates. This raises the question of whether the natural rates for each gene result from historical accidents, or are there rules that give certain combinations a selective advantage? We address this question using high-throughput measurements in rapidly growing cells from diverse organisms to find that about half of the rate combinations do not exist: genes that combine high transcription with low translation are strongly depleted. This depletion is due to a trade-off between precision and economy: high transcription decreases stochastic fluctuations but increases transcription costs. Our theory quantitatively explains which rate combinations are missing, and predicts the curvature of the fitness function for each gene. It may guide the design of gene circuits with desired expression levels and noise.
OLV
April 1, 2019
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Continuum of Gene-Expression Profiles Provides Spatial Division of Labor within a Differentiated Cell Type 2019 CELL SYSTEMS Volume: 8, Issue: 1 Miri Adler, Yael Korem Kohanim, Avichai Tendler, Avi Mayo, Uri Alon Weizmann Institute of Science
Single-cell gene expression reveals the diversity within a differentiated cell type. Often, cells of the same type show a continuum of gene-expression patterns. The origin of such continuum gene-expression patterns is unclear. To address this, we develop a theory to understand how a continuum provides division of labor in a tissue in which cells collectively contribute to several tasks. We find that a continuum is optimal when there are spatial gradients in the tissue that affect the performance in each task. The continuum is bounded inside a polyhedron whose vertices are expression profiles optimal at each task. We test this using single-cell gene expression for intestinal villi and liver hepatocytes, which form a curved 1D trajectory and a full 3D tetrahedron in gene-expression space, respectively. We infer the tasks for both cell types and characterize the spatial zonation of the task-specialist cells. This approach can be generally applied to other tissues.
OLV
April 1, 2019
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Calcium as a signal integrator in developing epithelial tissues. Brodskiy PA, Zartman JJ. Phys Biol. 2018 May 16;15(5):051001. doi: 10.1088/1478-3975/aabb18.
Decoding how tissue properties emerge across multiple spatial and temporal scales from the integration of local signals is a grand challenge in quantitative biology. For example, the collective behavior of epithelial cells is critical for shaping developing embryos. Understanding how epithelial cells interpret a diverse range of local signals to coordinate tissue-level processes requires a systems-level understanding of development. Integration of multiple signaling pathways that specify cell signaling information requires second messengers such as calcium ions. Increasingly, specific roles have been uncovered for calcium signaling throughout development. Calcium signaling regulates many processes including division, migration, death, and differentiation. However, the pleiotropic and ubiquitous nature of calcium signaling implies that many additional functions remain to be discovered. Quantitative imaging and computational modeling have provided important insights into how calcium signaling integration occurs. Reverse-engineering the conserved features of signal integration mediated by calcium signaling will enable novel approaches in regenerative medicine and synthetic control of morphogenesis.
many additional functions remain to be discovered? Oh, no! Reverse-engineering? Wow! Bottom line: many new papers increasingly make it harder for the “Darwinism of the gaps” to coherently and comprehensively explain things in biology. No surprise that some of their former comrades are desperately jumping off their sinking ship, clinging to anything that appears to float, hoping to get rescued by another passing by ship. :)OLV
March 30, 2019
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A Molecular Tension Sensor for N-Cadherin Reveals Distinct Forms of Mechanosensitive Adhesion Assembly in Adherens and Synaptic Junctions Ishaan Puranam, Aarti Urs, Brenna Kirk, Karen Newell-Litwa, Brenton Hoffman doi: https://doi.org/10.1101/552802
N-cadherin tension is subject to cell type specific regulation and mechanosensitive signaling occurs within SJs. Within tissues, the primary functions of cell-cell adhesions are to enable structure formation, maintain mechanical integrity, and facilitate signal transmission [1, 2]. These functions require cell-cell adhesions to resist mechanical loads. This is enabled by a variety of sub-cellular structures, such as adherens junctions (AJs) and synaptic junctions (SJs), in different cellular contexts. Traditionally, the mechanical integrity of these structures is thought to be mediated by cadherins, a large family of transmembrane proteins with over 100 members [3]. These proteins simultaneously form calcium-dependent adhesive interactions between cells, and link to the stiff actin cytoskeleton through interactions with catenins and a variety of other scaffolding proteins [1, 4]. However, recent advances in the emerging field of mechanobiology have demonstrated that cell-cell adhesion is not solely mediated by the passive, adhesive interactions of cadherins and other proteins. Instead, tensile forces play a key role in the formation and stabilization of cell-cell adhesions [5-10]. These tensile forces activate mechanosensitive signaling pathways through the alternation of protein conformations and the formation of new protein-protein interactions. Most research has focused on the mechanobiology of AJs formed by epithelial or endothelial cells, which are mediated by the classical cadherins E-cadherin and VE-cadherin, respectively [1, 11]. Excitingly, these studies are revealing new insights into the mechanical aspects of tissue development, wound healing, and the initiation of mechanosensitive diseases including cancer and atherosclerosis; however, the mechanosensitive roles of the other cadherin family members in various tissue types are not as well understood. A key next step will be further elucidating the mechanosensitive signaling pathways activated by the loading of AJs and SJs. This may be key to the complex signaling that likely underlies likely complex long-term biological processes, such as synaptic maturation and LTP. Notably, the RhoGTPases are also known to be subject to mechanosensitive regulation and play key roles in AJ assembly as well as synapse development. In particular, the regulation of RhoGTPases during LTP consolidation is particularly complex. Notably, key regulators of RhoGTPases that preferentially affect each stage of synaptic development, including a variety of GEFs and GAPs as well RhoGDI, have been identified [78]. A major question for future work will be determine if these regulators are subject to mechanosensitive regulation.
Functional complexity and complex functionality.OLV
March 23, 2019
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Detection of Dynamic Spatiotemporal Response to Periodic Chemical Stimulation in a Xenopus Embryonic Tissue YongTae Kim, Sagar D. Joshi, [...], and Lance A. Davidson PLoS One. 2011; 6(1): e14624. doi: 10.1371/journal.pone.0014624
Embryonic development is guided by a complex and integrated set of stimuli that results in collective system-wide organization that is both time and space regulated. These regulatory interactions result in the emergence of highly functional units, which are correlated to frequency-modulated stimulation profiles. Embryonic development is a complex, dynamic and highly regulated feedback process where cells actively respond to and exert control over their environment to form intact tissues, which results in functioning organ systems Gradients of chemical factors drive emergent phenomena in embryos by stimulating cascades of cell signaling, gene regulatory networks, cell motility, and cell differentiation. Together, these cues provide positional information to establish distinct cell identities that self-assemble into functional tissues.
OLV
March 22, 2019
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Global Computational Biology Market Growth, Trends and Forecast (2019-2024): A $6.79 Billion Opportunity - ResearchAndMarkets.com The use of bioinformatics tools in life sciences has become necessary to analyze experimental data. The huge amounts of data pose a challenge for the biological community, as most biologists are not familiar with informatics and statistical interpretation. An interdisciplinary collaboration was started with an aim to address the need for biologists to understand biological data.OLV
March 20, 2019
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Post-Turing tissue pattern formation: Advent of mechanochemistry Felix Brinkmann, Moritz Mercker, [...], and Anna Marciniak-Czochra PLoS Comput Biol. 2018 Jul; 14(7): e1006259. doi: 10.1371/journal.pcbi.1006259
Chemical and mechanical pattern formation is fundamental during embryogenesis and tissue development. Yet, the underlying molecular and cellular mechanisms are still elusive in many cases. the main contradictions arising in the framework of purely chemical theories are naturally and automatically resolved using the mechanochemical patterning theory. During embryogenesis, biological tissues gradually increase their complexity by self-organised creation of diverse chemical and mechanical patterns. Detailed mechanisms driving and controlling these patterns are not well understood. The presented modelling approach can be used to combine simulations with recent experimental developments, to help unravel one of the big mysteries in biology: The mechanisms of self-organised pattern formation during embryogenesis. the knowledge about how chemical patterns are produced, controlled, and how they interact with mechanical patterns is still very unsatisfactory. this [Turing] theory is not devoid of serious difficulties an appropriate candidate for the long-range inhibitor is still missing in many cases mechanical cues can be translated in various ways in order to influence and control chemical patterns, leading to the rapidly evolving research area of mechanotransduction in cell biology tissue mechanics is increasingly moving into focus to explain features of pattern formation which have been previously ascribed to diffusing molecules according to the Turing theory. Notably, forces and flows generated by motor proteins or advection have been proposed to significantly increase diffusion rates for long-range inhibition However, a general mechanochemical theory for robust pattern formation is still missing. models investigating mechanochemical pattern formation are still rare. the presented approach may serve as a future basis of enhance interactions of experiments with simulation methods in order to further unravel one of the big mysteries in development: the self-organised generation of patterns and shapes.
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March 20, 2019
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Feather arrays are patterned by interacting signalling and cell density waves William K. W. Ho, Lucy Freem, [...], and Denis J. Headon, PLoS Biol. 2019 Feb; 17(2): e3000132. Published online 2019 Feb 21. doi: 10.1371/journal.pbio.3000132
Feathers are arranged in a precise pattern in avian skin. They first arise during development in a row along the dorsal midline, with rows of new feather buds added sequentially in a spreading wave. a reaction-diffusion-taxis system, integrated with mechanical processes, generates the feather array. In flighted birds, the key role of the EDA/Ectodysplasin A receptor (EDAR) pathway in vertebrate skin patterning has been recast to activate this process in a quasi-1-dimensional manner, imposing highly ordered pattern formation. the manner of wave loss differs in different species, with ostrich embryos lacking the wave of EDA, whereas the emu lacks sufficient skin cells at the appropriate developmental stage to make precisely organised feather rudiments. A number of theoretical mechanisms to explain the spontaneous emergence of periodicity in biological systems have been proposed Our present work uncovers a distinct process normally operating in avian skin, in which elements of both reaction-diffusion and cell movement–based patterning systems are integrated into a unified periodicity-generating mechanism. In avian skin, we report a hybrid of these conceptual systems, a reaction-diffusion-taxis mechanism integrated with mechanical processes. These local patterning interactions are triggered within the broad field of the skin by the passing of a travelling EDA wave, imposing the construction of a precise hexagonal lattice of feather primordia.
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March 20, 2019
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Altered Gene Regulatory Networks Are Associated With the Transition From C3 to Crassulacean Acid Metabolism in Erycina (Oncidiinae: Orchidaceae) Karolina Heyduk, Michelle Hwang, [...], and Jim Leebens-Mack Front Plant Sci. 2018; 9: 2000. doi: 10.3389/fpls.2018.02000
the growing evidence suggests that the secondary processes that make a CAM plant, including stomatal regulation, light sensing and downstream transcriptional responses, and carbohydrate metabolism feedbacks, undergo fine-tuning along the evolutionary trajectory between C3 and CAM. Further work that characterizes closely related C3 and CAM species has the potential to greatly advance our understanding of the integration of nighttime CO2 acquisition with more complex regulatory pathways.
How can that fine-tuning happen?OLV
March 20, 2019
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Leader of the SAC: molecular mechanisms of Mps1/TTK regulation in mitosis Spyridon T. Pachis and Geert J. P. L. Kops Open Biol. 2018 Aug; 8(8): 180109. doi: 10.1098/rsob.180109
how exactly does inactivation take place and what are the dynamics of it? where this residual Mps1 is binding and how much reduction of Mps1 levels is sufficient to tip the balance in favour of the phosphatases and switch off SAC signalling. Elucidating the finer points of Mps1 regulation in the coming years will provide crucial insights into how genomic stability is ensured.
OLV
March 18, 2019
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Leader of the SAC: molecular mechanisms of Mps1/TTK regulation in mitosis Spyridon T. Pachis and Geert J. P. L. Kops Open Biol. 2018 Aug; 8(8): 180109. doi: 10.1098/rsob.180109
The recent finding of a possible inactive ‘prone-to-autophosphorylate’ conformer of Mps1 involving the NTE implies an even more complex activation mechanism than currently envisioned How exactly are Aurora B and ARHGEF17 involved in these initial Mps1–kinetochore interactions ? Have all contributing factors been identified?
Oh, no! More complex?OLV
March 18, 2019
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Leader of the SAC: molecular mechanisms of Mps1/TTK regulation in mitosis Spyridon T. Pachis and Geert J. P. L. Kops Open Biol. 2018 Aug; 8(8): 180109. doi: 10.1098/rsob.180109
how localization and activity of the chief executive officer of the SAC, the kinase Mps1, is regulated. Understanding its role in the protection of genome stability is far from complete, however, and several key lacunas need to be filled. Very little is known about how and where this pool of Mps1 becomes activated. Upon entry into mitosis, Mps1 recruitment to unattached kinetochores is necessary for the wave of activation that is needed to mount a full SAC response. Several questions as to how this is achieved are as yet unanswered. How does dimerization of Mps1 occur and how does it affect the activation dynamics of the kinase? What are the steps leading to full activation of the kinase, and what are the roles of specific NTE and MR modifications?
OLV
March 18, 2019
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The dynein adaptor Hook2 plays essential roles in mitotic progression and cytokinesis Devashish Dwivedi, Amrita Kumari, […], and Mahak Sharma J Cell Biol. 2019 Mar 4; 218(3): 871–894. doi: 10.1083/jcb.201804183
Another important question is to elucidate the precise mechanism by which Hook2 regulates MT nucleation. As centrosomal levels of ?-tubulin were unaffected upon Hook2 depletion, it is possible that Hook2 either directly or indirectly modulates ?-TURC nucleation activity. Future studies would provide new insights into Hook2 function and illuminate the regulatory mechanisms that govern its function as a dynein–dynactin adaptor.
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March 18, 2019
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The dynein adaptor Hook2 plays essential roles in mitotic progression and cytokinesis Devashish Dwivedi, Amrita Kumari, […], and Mahak Sharma J Cell Biol. 2019 Mar 4; 218(3): 871–894. doi: 10.1083/jcb.201804183
we cannot determine the mechanism underlying dynactin-dependent targeting of the centralspindlin complex to the midzone. To precisely understand the role of dynactin in midzone recruitment of centralspindlin subunits, it would be important in future studies to use targeted approaches of inhibiting dynactin function specifically at the central spindle. It would be relevant to determine whether the role of Hook2 as a dynein–dynactin linker is required for endosomal trafficking within the midbody.
OLV
March 18, 2019
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PavelU @13: Is OLV’s comment @11 also off topic? BTW, do you have any objections for BA77’s comments @1 and @2 ? Are they within topic?jawa
March 18, 2019
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The dynein adaptor Hook2 plays essential roles in mitotic progression and cytokinesis Devashish Dwivedi, Amrita Kumari, [...], and Mahak Sharma J Cell Biol. 2019 Mar 4; 218(3): 871–894. doi: 10.1083/jcb.201804183
Hook proteins are evolutionarily conserved dynein adaptors that promote assembly of highly processive dynein–dynactin motor complexes. Mammals express three Hook paralogs, namely Hook1, Hook2, and Hook3, that have distinct subcellular localizations and expectedly, distinct cellular functions. Hook2 binds to and promotes dynein–dynactin assembly specifically during mitosis. During the late G2 phase, Hook2 mediates dynein–dynactin localization at the nuclear envelope (NE), which is required for centrosome anchoring to the NE. Independent of its binding to dynein, Hook2 regulates microtubule nucleation at the centrosome; accordingly, Hook2-depleted cells have reduced astral microtubules and spindle positioning defects. Besides the centrosome, Hook2 localizes to and recruits dynactin and dynein to the central spindle. Dynactin-dependent targeting of centralspindlin complex to the midzone is abrogated upon Hook2 depletion; accordingly, Hook2 depletion results in cytokinesis failure. the zebrafish Hook2 homologue promotes dynein–dynactin association and was essential for zebrafish early development. Together, these results suggest that Hook2 mediates assembly of the dynein–dynactin complex and regulates mitotic progression and cytokinesis.
In this case gpuccio’s insightful analysis of the involved proteins would have been a delightful treat that is missed here. Are there any detectable information jumps here too? Definitely missing those comments and OPs.OLV
March 18, 2019
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PeterA @16: I corrected jawa's misunderstanding about "off topic", which invalidated his question.PavelU
March 17, 2019
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PavelU @15: Did you respond jawa's question @14?PeterA
March 17, 2019
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jawa, That's not my rule. It's a commonly accepted standard that you should be aware of too.PavelU
March 17, 2019
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PavelU @13, Is OLV's comment @11 also off topic according to your rule?jawa
March 17, 2019
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PaoloV @12: Your theological comment is off topic, for this is a purely scientific discussion, as you may see in the OP headline. Note that it clearly shows that the main topic is Cell Biology.PavelU
March 17, 2019
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OLV, No, that’s not amazing at all. Actually, it’s written in the Christian Scriptures, which refer to all the people “who by their unrighteousness suppress the truth. For what can be known about God is plain to them, because God has shown it to them. For His invisible attributes, namely, His eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made. So they are without excuse.” Romans 1:18-20 It’s basically our sinful condition that explains our natural rebellious attitude of rejection of the truth.PaoloV
March 17, 2019
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Isn’t it really amazing that someone could seriously believe that all the above posted examples of fascinating biological choreographies are the result of natural (unguided) evolutionary processes?OLV
March 17, 2019
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Mechanisms of Spindle Positioning: Lessons from Worms and Mammalian Cells Sachin Kotak Biomolecules 2019, 9(2), 80; doi:10.3390/biom9020080
it is becoming more apparent that cortical actin and its associated proteins play a crucial role of spindle positioning, but whether these players directly or indirectly affect spindle positioning by modulating the localization/activity of the ternary complex and dynein remains elusive. It would be equally important to test if analogous to mammalian cells in culture, whether various mammalian tissues also employ multiple mitotic kinases to fine-tune accurate positioning of their spindle in a spatiotemporal manner. how mechanical cues are guiding chemical machinery to orient mitotic spindle is not yet very much evident, and thus new data in this theme will definitely strengthen our current understanding. exciting time lie ahead of us where we can expect novel insights in the theme of spatial and temporal regulation of spindle positioning for error-free cell division.
OLV
March 17, 2019
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Mechanisms of Spindle Positioning: Lessons from Worms and Mammalian Cells Sachin Kotak Biomolecules 2019, 9(2), 80; doi:10.3390/biom9020080
Proper positioning of the mitotic spindle is fundamental for specifying the site for cleavage furrow, and thus regulates the appropriate sizes and accurate distribution of the cell fate determinants in the resulting daughter cells during development and in the stem cells. how the abovementioned components precisely and spatiotemporally regulate spindle positioning by sensing the physicochemical environment for execution of flawless mitosis. To efficiently grow and divide, all cells undergo a series of tightly regulated events known as the cell cycle. In eukaryotes, the cell cycle comprises Interphase and M-phase. M-phase is further divided into mitosis (or meiosis in germ cells) and cytokinesis. During mitosis, all animal cells establish an elegant diamond-shaped microtubule-based structure known as a mitotic spindle that is critical for ensuring error-free partitioning of the genomic, as well as intracellular contents the accurate positioning of the mitotic spindle is critical for the correct placement of the cleavage furrow, relative sizes and spatial organization of the daughter cells, and faithful segregation of the cell fate determinants during asymmetric cell divisions including in the stem cells most of these mechanisms primarily rely on the dynamic astral microtubules that emanate from the centrosomes. cells also possess mechanisms whereby they rely on external mechanical signals to instruct the intracellular chemical environment to align the mitotic spindle correctly. how this intricate machinery spatiotemporally coordinate with mitotic progression to ensure proper spindle positioning. the importance of upstream polarity regulators in guiding spindle positioning new paradigms whereby extrinsic physical and chemical signals are shown to modulate spindle positioning interesting remaining questions; answering those will be helpful for better understanding the underlying mechanisms of spindle positioning The inherent ability of the mitotic spindle to position in the particular reference axis is vital to generate cell fate diversity and to ensure that cells are organized in a proper three-dimensional arrangement within a tissue. despite the discovery of several sophisticated building blocks that organize and spatiotemporally control spindle positioning, our understanding how these individual pieces collectively communicate to regulate spindle positioning is still far from clear.
OLV
March 17, 2019
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Overcoming the Cost of Positive Autoregulation by Accelerating the Response with a Coupled Negative Feedback Rong Gao and Ann M. Stock Cell Rep. 2018 Sep 11; 24(11): 3061–3071.e6. doi: 10.1016/j.celrep.2018.08.023
“...the effectiveness of such a regulatory strategy [...] to circumvent the trade-off between response speed and expression level.” This strategy offers great flexibility in fine-tuning the response speed as well as the expression level. It remains to be explored how many TFs share the mechanism [...] to reconcile different fitness requirements. another yet unknown negative feedback may operate in the engineered system.
OLV
March 16, 2019
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BA 77: “the ‘bottom up’ reductive materialistic framework of Darwinian evolution is found to be grossly inadequate, especially when considering ‘positional information’, for explaining how any particular organism might achieve its basic form.” Yes. Well stated.OLV
March 16, 2019
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Overcoming the Cost of Positive Autoregulation by Accelerating the Response with a Coupled Negative Feedback Rong Gao and Ann M. Stock Cell Rep. 2018 Sep 11; 24(11): 3061–3071.e6. doi: 10.1016/j.celrep.2018.08.023
Cells have [...] complex gene regulatory networks to produce appropriate amounts of proteins at appropriate times to adapt to ever-changing environments. A few recurring network motifs, such as feed-forward loops and autoregulatory circuits, constitute the basic building blocks for more sophisticated regulatory networks A fundamental trade-off between rapid response and optimal expression of genes below cytotoxic levels exists for many signaling circuits, particularly for positively autoregulated systems with an inherent response delay. Coupled negative autoregulation is discovered to allow a strong promoter for fast response without incurring cost of increasing protein expression levels.
OLV
March 15, 2019
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Mathematical modeling of movement on fitness landscapes Nishant Gerald, Dibyendu Dutta, R. G. Brajesh and Supreet SainiEmail author BMC Systems Biology DOI: 10.1186/s12918-019-0704-0
exponential or normal distributions can statistically approximate the distribution of mutational effects to a satisfactory degree. This is especially true when the starting fitness corresponding to a particular set is low (compared to the peak permissible fitness). What distribution of a parameter value in its prescribed range results in an exponential or a normal distribution, however, remains an open question.
OLV
March 15, 2019
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The proneural wave in the Drosophila optic lobe is driven by an excitable reaction-diffusion mechanism David J Jörg, Elizabeth E Caygill, [...], and Benjamin D Simons eLife. 2019; 8: e40919. doi: 10.7554/eLife.40919
In living organisms, self-organised waves of signalling activity propagate spatiotemporal information within tissues. this ‘proneural wave’ is driven by an excitable reaction-diffusion system involving epidermal growth factor receptor (EGFR) signalling interacting with the proneural gene l’sc. The development of multicellular organisms relies on a multitude of transient coordination processes that provide the spatiotemporal cues for cell fate decision-making and thereby ensure that tissues are specified with the correct size, pattern and composition the proneural wave involves the activation of an excitatory pulse of signalling activity and gene expression, giving rise to a tightly-regulated propagating transition zone. such a mechanism may serve more widely as a generic and robust strategy to achieve sequential transition waves in developing tissues.
OLV
March 15, 2019
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