scholarly journals Loss of growth homeostasis by genetic decoupling of cell division from biomass growth: implication for size control mechanisms

2014 ◽  
Vol 10 (12) ◽  
pp. 769 ◽  
Author(s):  
Hannah Schmidt‐Glenewinkel ◽  
Naama Barkai
Keyword(s):  
Cell Division ◽  
Size Control ◽  
Control Mechanisms ◽  
Biomass Growth

scholarly journals Concentration fluctuations due to size-dependent gene expression and cell-size control mechanisms

2021 ◽  
Author(s):  
Chen Jia ◽  
Abhyudai Singh ◽  
Ramon Grima
Keyword(s):  
Gene Expression ◽  
Cell Division ◽  
Cell Size ◽  
Gene Dosage ◽  
Size Control ◽  
Reaction Rates ◽  
Concentration Fluctuations ◽  
Cycle Phase ◽  
Control Mechanisms ◽  
Size Dependent

Intracellular reaction rates depend on concentrations and hence their levels are often regulated. However classical models of stochastic gene expression lack a cell size description and cannot be used to predict noise in concentrations. Here, we construct a model of gene product dynamics that includes a description of cell growth, cell division, size-dependent gene expression, gene dosage compensation, and size control mechanisms that can vary with the cell cycle phase. We obtain expressions for the approximate distributions and power spectra of concentration fluctuations which lead to insight into the emergence of concentration homeostasis. Furthermore, we find that (i) the conditions necessary to suppress cell division-induced concentration oscillations are difficult to achieve; (ii) mRNA concentration and number distributions can have different number of modes; (iii) certain size control strategies are ideal because they maintain constant mean concentrations whilst minimising concentration noise. Predictions are confirmed using lineage data for E. coli, fission yeast and budding yeast.

scholarly journals Dissecting the Control Mechanisms for DNA Replication and Cell Division in E. coli

Cell Reports ◽  
2018 ◽  
Vol 25 (3) ◽  
pp. 761-771.e4 ◽  
Author(s):  
Gabriele Micali ◽  
Jacopo Grilli ◽  
Jacopo Marchi ◽  
Matteo Osella ◽  
Marco Cosentino Lagomarsino
Keyword(s):  
Cell Division ◽  
Dna Replication ◽  
Control Mechanisms ◽  
E Coli

scholarly journals Control mechanisms af cell division and radiation

1969 ◽  
Vol 9 (1) ◽  
pp. 21-33
Author(s):  
Yukio DOIDA
Keyword(s):  
Cell Division ◽  
Control Mechanisms

scholarly journals Cortical regulation of cell size by a sizer cdr2p

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Kally Z Pan ◽  
Timothy E Saunders ◽  
Ignacio Flor-Parra ◽  
Martin Howard ◽  
Fred Chang
Keyword(s):  
Cell Division ◽  
Protein Kinase ◽  
Cell Surface ◽  
Surface Area ◽  
Control Mechanism ◽  
Size Control ◽  
Mitotic Entry ◽  
Medial Cortex ◽  
Peripheral Membrane Protein ◽  
Dose Dependent

Cells can, in principle, control their size by growing to a specified size before commencing cell division. How any cell actually senses its own size remains poorly understood. The fission yeast Schizosaccharomyces pombe are rod-shaped cells that grow to ∼14 µm in length before entering mitosis. In this study, we provide evidence that these cells sense their surface area as part of this size control mechanism. We show that cells enter mitosis at a certain surface area, as opposed to a certain volume or length. A peripheral membrane protein kinase cdr2p has properties of a dose-dependent ‘sizer’ that controls mitotic entry. As cells grow, the local cdr2p concentration in nodes at the medial cortex accumulates as a measure of cell surface area. Our findings, which challenge a previously proposed pom1p gradient model, lead to a new model in which cells sense their size by using cdr2p to probe the surface area over the whole cell and relay this information to the medial cortex.

scholarly journals Unconventional cell division cycles from marine-derived yeasts

2019 ◽  
Author(s):  
Lorna M.Y. Mitchison-Field ◽  
José M. Vargas-Muñiz ◽  
Benjamin M. Stormo ◽  
Ellysa J.D. Vogt ◽  
Sarah Van Dierdonck ◽  
...  
Keyword(s):  
Cell Division ◽  
Cell Polarity ◽  
Stress Resistance ◽  
Size Control ◽  
Time Lapse ◽  
Model System ◽  
Black Yeasts ◽  
Differential Interference Contrast ◽  
Marine Habitat ◽  
Unique Species

AbstractFungi have been found in every marine habitat that has been explored, however, the diversity and functions of fungi in the ocean are poorly understood. In this study, fungi were cultured from the marine environment in the vicinity of Woods Hole, MA, USA including from plankton, sponge and coral. Our sampling resulted in 36 unique species across 20 genera. We observed many isolates by time-lapse differential interference contrast (DIC) microscopy and analyzed modes of growth and division. Several black yeasts displayed highly unconventional cell division cycles compared to those of traditional model yeast systems. Black yeasts have been found in habitats inhospitable to other life and are known for halotolerance, virulence, and stress-resistance. We find that this group of yeasts also shows remarkable plasticity in terms of cell size control, modes of cell division, and cell polarity. Unexpected behaviors include division through a combination of fission and budding, production of multiple simultaneous buds, and cell division by sequential orthogonal septations. These marine-derived yeasts reveal alternative mechanisms for cell division cycles that seem likely to expand the repertoire of rules established from classic model system yeasts.

scholarly journals A note on noise suppression in cell-size control

2017 ◽  
Author(s):  
Abhyudai Singh
Keyword(s):  
Cell Division ◽  
Cell Size ◽  
Noise Suppression ◽  
Essential Feature ◽  
Size Control ◽  
Cell Types ◽  
Cellular Growth ◽  
Model Parameters ◽  
Division Rate ◽  
Newborn Size

AbstractDiverse cell types employ mechanisms to maintain size homeostasis and minimize aberrant fluctuations in cell size. It is well known that exponential cellular growth can drive unbounded intercellular variations in cell size, if the timing of cell division is size independent. Hence coupling of division timing to size is an essential feature of size control. We formulate a stochastic model, where exponential cellular growth is coupled with random cell division events, and the rate at which division events occur increases as a power function of cell size. Interestingly, in spite of nonlinearities in the stochastic dynamical model, statistical moments of the newborn cell size can be determined in closed form, providing fundamental limits to suppression of size fluctuations. In particular, formulas reveal that the magnitude of fluctuations in the newborn size is determined by the inverse of the size exponent in the division rate, and this relationship is independent of other model parameters, such as the growth rate. We further expand these results to consider randomness in the partitioning of mother cell size among daughters at the time of division. The sensitivity of newborn size fluctuations to partitioning noise is found to monotonically decrease, and approach a non-zero value, with increasing size exponent in the division rate. Finally, we discuss how our analytical results provide limits on noise control in commonly used models for cell size regulation.

scholarly journals A new class of cyclin dependent kinase in Chlamydomonas is required for coupling cell size to cell division

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Yubing Li ◽  
Dianyi Liu ◽  
Cristina López-Paz ◽  
Bradley JSC Olson ◽  
James G Umen
Keyword(s):  
Cell Division ◽  
Cell Size ◽  
Mother Cell ◽  
Size Control ◽  
Mitotic Division ◽  
General Mechanism ◽  
Cell Cycle Regulators ◽  
Proliferating Cells ◽  
Multiple Fission ◽  
Division Number

Proliferating cells actively control their size by mechanisms that are poorly understood. The unicellular green alga Chlamydomonas reinhardtii divides by multiple fission, wherein a ‘counting’ mechanism couples mother cell-size to cell division number allowing production of uniform-sized daughters. We identified a sizer protein, CDKG1, that acts through the retinoblastoma (RB) tumor suppressor pathway as a D-cyclin-dependent RB kinase to regulate mitotic counting. Loss of CDKG1 leads to fewer mitotic divisions and large daughters, while mis-expression of CDKG1 causes supernumerous mitotic divisions and small daughters. The concentration of nuclear-localized CDKG1 in pre-mitotic cells is set by mother cell size, and its progressive dilution and degradation with each round of cell division may provide a link between mother cell-size and mitotic division number. Cell-size-dependent accumulation of limiting cell cycle regulators such as CDKG1 is a potentially general mechanism for size control.

scholarly journals Localized JNK signaling regulates organ size during development

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Helen Rankin Willsey ◽  
Xiaoyan Zheng ◽  
José Carlos Pastor-Pareja ◽  
A Jeremy Willsey ◽  
Philip A Beachy ◽  
...  
Keyword(s):  
Hedgehog Signaling ◽  
Hippo Pathway ◽  
Size Control ◽  
Organ Size ◽  
Control Mechanisms ◽  
Cancer Therapies ◽  
Independent Manner ◽  
Jnk Signaling ◽  
New Strategy ◽  
The Hippo Pathway

A fundamental question of biology is what determines organ size. Despite demonstrations that factors within organs determine their sizes, intrinsic size control mechanisms remain elusive. Here we show that Drosophila wing size is regulated by JNK signaling during development. JNK is active in a stripe along the center of developing wings, and modulating JNK signaling within this stripe changes organ size. This JNK stripe influences proliferation in a non-canonical, Jun-independent manner by inhibiting the Hippo pathway. Localized JNK activity is established by Hedgehog signaling, where Ci elevates dTRAF1 expression. As the dTRAF1 homolog, TRAF4, is amplified in numerous cancers, these findings provide a new mechanism for how the Hedgehog pathway could contribute to tumorigenesis, and, more importantly, provides a new strategy for cancer therapies. Finally, modulation of JNK signaling centers in developing antennae and legs changes their sizes, suggesting a more generalizable role for JNK signaling in developmental organ size control.

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