@article{6897,
  abstract     = {The apical hook is a transiently formed structure that plays a protective role when the germinating seedling penetrates through the soil towards the surface. Crucial for proper bending is the local auxin maxima, which defines the concave (inner) side of the hook curvature. As no sign of asymmetric auxin distribution has been reported in embryonic hypocotyls prior to hook formation, the question of how auxin asymmetry is established in the early phases of seedling germination remains largely unanswered. Here, we analyzed the auxin distribution and expression of PIN auxin efflux carriers from early phases of germination, and show that bending of the root in response to gravity is the crucial initial cue that governs the hypocotyl bending required for apical hook formation. Importantly, polar auxin transport machinery is established gradually after germination starts as a result of tight root-hypocotyl interaction and a proper balance between abscisic acid and gibberellins.},
  author       = {Zhu, Qiang and Gallemi, Marçal and Pospíšil, Jiří and Žádníková, Petra and Strnad, Miroslav and Benková, Eva},
  issn         = {14779129},
  journal      = {Development},
  number       = {17},
  publisher    = {The Company of Biologists},
  title        = {{Root gravity response module guides differential growth determining both root bending and apical hook formation in Arabidopsis}},
  doi          = {10.1242/dev.175919},
  volume       = {146},
  year         = {2019},
}

@article{6898,
  abstract     = {Background

Chlamydia are ancient intracellular pathogens with reduced, though strikingly conserved genome. Despite their parasitic lifestyle and isolated intracellular environment, these bacteria managed to avoid accumulation of deleterious mutations leading to subsequent genome degradation characteristic for many parasitic bacteria.
Results

We report pan-genomic analysis of sixteen species from genus Chlamydia including identification and functional annotation of orthologous genes, and characterization of gene gains, losses, and rearrangements. We demonstrate the overall genome stability of these bacteria as indicated by a large fraction of common genes with conserved genomic locations. On the other hand, extreme evolvability is confined to several paralogous gene families such as polymorphic membrane proteins and phospholipase D, and likely is caused by the pressure from the host immune system.
Conclusions

This combination of a large, conserved core genome and a small, evolvable periphery likely reflect the balance between the selective pressure towards genome reduction and the need to adapt to escape from the host immunity.},
  author       = {Sigalova, Olga M. and Chaplin, Andrei V. and Bochkareva, Olga and Shelyakin, Pavel V. and Filaretov, Vsevolod A. and Akkuratov, Evgeny E. and Burskaia, Valentina and Gelfand, Mikhail S.},
  issn         = {14712164},
  journal      = {BMC Genomics},
  number       = {1},
  publisher    = {BioMed Central},
  title        = {{Chlamydia pan-genomic analysis reveals balance between host adaptation and selective pressure to genome reduction}},
  doi          = {10.1186/s12864-019-6059-5},
  volume       = {20},
  year         = {2019},
}

@article{6899,
  abstract     = {Intra-organ communication guides morphogenetic processes that are essential for an organ to carry out complex physiological functions. In the heart, the growth of the myocardium is tightly coupled to that of the endocardium, a specialized endothelial tissue that lines its interior. Several molecular pathways have been implicated in the communication between these tissues including secreted factors, components of the extracellular matrix, or proteins involved in cell-cell communication. Yet, it is unknown how the growth of the endocardium is coordinated with that of the myocardium. Here, we show that an increased expansion of the myocardial atrial chamber volume generates higher junctional forces within endocardial cells. This leads to biomechanical signaling involving VE-cadherin, triggering nuclear localization of the Hippo pathway transcriptional regulator Yap1 and endocardial proliferation. Our work suggests that the growth of the endocardium results from myocardial chamber volume expansion and ends when the tension on the tissue is relaxed.},
  author       = {Bornhorst, Dorothee and Xia, Peng and Nakajima, Hiroyuki and Dingare, Chaitanya and Herzog, Wiebke and Lecaudey, Virginie and Mochizuki, Naoki and Heisenberg, Carl-Philipp J and Yelon, Deborah and Abdelilah-Seyfried, Salim},
  issn         = {20411723},
  journal      = {Nature communications},
  number       = {1},
  pages        = {4113},
  publisher    = {Nature Publishing Group},
  title        = {{Biomechanical signaling within the developing zebrafish heart attunes endocardial growth to myocardial chamber dimensions}},
  doi          = {10.1038/s41467-019-12068-x},
  volume       = {10},
  year         = {2019},
}

@article{6900,
  abstract     = {Across diverse biological systems—ranging from neural networks to intracellular signaling and genetic regulatory networks—the information about changes in the environment is frequently encoded in the full temporal dynamics of the network nodes. A pressing data-analysis challenge has thus been to efficiently estimate the amount of information that these dynamics convey from experimental data. Here we develop and evaluate decoding-based estimation methods to lower bound the mutual information about a finite set of inputs, encoded in single-cell high-dimensional time series data. For biological reaction networks governed by the chemical Master equation, we derive model-based information approximations and analytical upper bounds, against which we benchmark our proposed model-free decoding estimators. In contrast to the frequently-used k-nearest-neighbor estimator, decoding-based estimators robustly extract a large fraction of the available information from high-dimensional trajectories with a realistic number of data samples. We apply these estimators to previously published data on Erk and Ca2+ signaling in mammalian cells and to yeast stress-response, and find that substantial amount of information about environmental state can be encoded by non-trivial response statistics even in stationary signals. We argue that these single-cell, decoding-based information estimates, rather than the commonly-used tests for significant differences between selected population response statistics, provide a proper and unbiased measure for the performance of biological signaling networks.},
  author       = {Cepeda Humerez, Sarah A and Ruess, Jakob and Tkačik, Gašper},
  issn         = {15537358},
  journal      = {PLoS computational biology},
  number       = {9},
  pages        = {e1007290},
  publisher    = {Public Library of Science},
  title        = {{Estimating information in time-varying signals}},
  doi          = {10.1371/journal.pcbi.1007290},
  volume       = {15},
  year         = {2019},
}

@unpublished{10065,
  abstract     = {We study double quantum dots in a Ge/SiGe heterostructure and test their maturity towards singlet-triplet ($S-T_0$) qubits. We demonstrate a large range of tunability, from two single quantum dots to a double quantum dot. We measure Pauli spin blockade and study the anisotropy of the $g$-factor. We use an adjacent quantum dot for sensing charge transitions in the double quantum dot at interest. In conclusion, Ge/SiGe possesses all ingredients necessary for building a singlet-triplet qubit.},
  author       = {Hofmann, Andrea C and Jirovec, Daniel and Borovkov, Maxim and Prieto Gonzalez, Ivan and Ballabio, Andrea and Frigerio, Jacopo and Chrastina, Daniel and Isella, Giovanni and Katsaros, Georgios},
  booktitle    = {arXiv},
  title        = {{Assessing the potential of Ge/SiGe quantum dots as hosts for singlet-triplet qubits}},
  doi          = {10.48550/arXiv.1910.05841},
  year         = {2019},
}

@inproceedings{10190,
  abstract     = {The verification of concurrent programs remains an open challenge, as thread interaction has to be accounted for, which leads to state-space explosion. Stateless model checking battles this problem by exploring traces rather than states of the program. As there are exponentially many traces, dynamic partial-order reduction (DPOR) techniques are used to partition the trace space into equivalence classes, and explore a few representatives from each class. The standard equivalence that underlies most DPOR techniques is the happens-before equivalence, however recent works have spawned a vivid interest towards coarser equivalences. The efficiency of such approaches is a product of two parameters: (i) the size of the partitioning induced by the equivalence, and (ii) the time spent by the exploration algorithm in each class of the partitioning. In this work, we present a new equivalence, called value-happens-before and show that it has two appealing features. First, value-happens-before is always at least as coarse as the happens-before equivalence, and can be even exponentially coarser. Second, the value-happens-before partitioning is efficiently explorable when the number of threads is bounded. We present an algorithm called value-centric DPOR (VCDPOR), which explores the underlying partitioning using polynomial time per class. Finally, we perform an experimental evaluation of VCDPOR on various benchmarks, and compare it against other state-of-the-art approaches. Our results show that value-happens-before typically induces a significant reduction in the size of the underlying partitioning, which leads to a considerable reduction in the running time for exploring the whole partitioning.},
  author       = {Chatterjee, Krishnendu and Pavlogiannis, Andreas and Toman, Viktor},
  booktitle    = {Proceedings of the 34th ACM International Conference on Object-Oriented Programming, Systems, Languages, and Applications},
  issn         = {2475-1421},
  keywords     = {safety, risk, reliability and quality, software},
  location     = {Athens, Greece},
  publisher    = {ACM},
  title        = {{Value-centric dynamic partial order reduction}},
  doi          = {10.1145/3360550},
  volume       = {3},
  year         = {2019},
}

@article{10354,
  abstract     = {Background
ESCRT-III is a membrane remodelling filament with the unique ability to cut membranes from the inside of the membrane neck. It is essential for the final stage of cell division, the formation of vesicles, the release of viruses, and membrane repair. Distinct from other cytoskeletal filaments, ESCRT-III filaments do not consume energy themselves, but work in conjunction with another ATP-consuming complex. Despite rapid progress in describing the cell biology of ESCRT-III, we lack an understanding of the physical mechanisms behind its force production and membrane remodelling.
Results
Here we present a minimal coarse-grained model that captures all the experimentally reported cases of ESCRT-III driven membrane sculpting, including the formation of downward and upward cones and tubules. This model suggests that a change in the geometry of membrane bound ESCRT-III filaments—from a flat spiral to a 3D helix—drives membrane deformation. We then show that such repetitive filament geometry transitions can induce the fission of cargo-containing vesicles.
Conclusions
Our model provides a general physical mechanism that explains the full range of ESCRT-III-dependent membrane remodelling and scission events observed in cells. This mechanism for filament force production is distinct from the mechanisms described for other cytoskeletal elements discovered so far. The mechanistic principles revealed here suggest new ways of manipulating ESCRT-III-driven processes in cells and could be used to guide the engineering of synthetic membrane-sculpting systems.},
  author       = {Harker-Kirschneck, Lena and Baum, Buzz and Šarić, Anđela},
  issn         = {1741-7007},
  journal      = {BMC Biology},
  keywords     = {cell biology},
  number       = {1},
  publisher    = {Springer Nature},
  title        = {{Changes in ESCRT-III filament geometry drive membrane remodelling and fission in silico}},
  doi          = {10.1186/s12915-019-0700-2},
  volume       = {17},
  year         = {2019},
}

@article{10355,
  abstract     = {The molecular machinery of life is largely created via self-organisation of individual molecules into functional assemblies. Minimal coarse-grained models, in which a whole macromolecule is represented by a small number of particles, can be of great value in identifying the main driving forces behind self-organisation in cell biology. Such models can incorporate data from both molecular and continuum scales, and their results can be directly compared to experiments. Here we review the state of the art of models for studying the formation and biological function of macromolecular assemblies in living organisms. We outline the key ingredients of each model and their main findings. We illustrate the contribution of this class of simulations to identifying the physical mechanisms behind life and diseases, and discuss their future developments.},
  author       = {Hafner, Anne E and Krausser, Johannes and Šarić, Anđela},
  issn         = {0959-440X},
  journal      = {Current Opinion in Structural Biology},
  keywords     = {molecular biology, structural biology},
  pages        = {43--52},
  publisher    = {Elsevier},
  title        = {{Minimal coarse-grained models for molecular self-organisation in biology}},
  doi          = {10.1016/j.sbi.2019.05.018},
  volume       = {58},
  year         = {2019},
}

@article{105,
  abstract     = {Clinical Utility Gene Card. 1. Name of Disease (Synonyms): Pontocerebellar hypoplasia type 9 (PCH9) and spastic paraplegia-63 (SPG63). 2. OMIM# of the Disease: 615809 and 615686. 3. Name of the Analysed Genes or DNA/Chromosome Segments: AMPD2 at 1p13.3. 4. OMIM# of the Gene(s): 102771.},
  author       = {Marsh, Ashley and Novarino, Gaia and Lockhart, Paul and Leventer, Richard},
  journal      = {European Journal of Human Genetics},
  pages        = {161--166},
  publisher    = {Springer Nature},
  title        = {{CUGC for pontocerebellar hypoplasia type 9 and spastic paraplegia-63}},
  doi          = {10.1038/s41431-018-0231-2},
  volume       = {27},
  year         = {2019},
}

@article{10619,
  abstract     = {The quantum anomalous Hall (QAH) effect combines topology and magnetism to produce precisely quantized Hall resistance at zero magnetic field. We report the observation of a QAH effect in twisted bilayer graphene aligned to hexagonal boron nitride. The effect is driven by intrinsic strong interactions, which polarize the electrons into a single spin- and valley-resolved moiré miniband with Chern number C = 1. In contrast to magnetically doped systems, the measured transport energy gap is larger than the Curie temperature for magnetic ordering, and quantization to within 0.1% of the von Klitzing constant persists to temperatures of several kelvin at zero magnetic field. Electrical currents as small as 1 nanoampere controllably switch the magnetic order between states of opposite polarization, forming an electrically rewritable magnetic memory.},
  author       = {Serlin, M. and Tschirhart, C. L. and Polshyn, Hryhoriy and Zhang, Y. and Zhu, J. and Watanabe, K. and Taniguchi, T. and Balents, L. and Young, A. F.},
  issn         = {1095-9203},
  journal      = {Science},
  keywords     = {multidisciplinary},
  number       = {6480},
  pages        = {900--903},
  publisher    = {American Association for the Advancement of Science},
  title        = {{Intrinsic quantized anomalous Hall effect in a moiré heterostructure}},
  doi          = {10.1126/science.aay5533},
  volume       = {367},
  year         = {2019},
}

@article{10621,
  abstract     = {Twisted bilayer graphene has recently emerged as a platform for hosting correlated phenomena. For twist angles near θ ≈ 1.1°, the low-energy electronic structure of twisted bilayer graphene features isolated bands with a flat dispersion1,2. Recent experiments have observed a variety of low-temperature phases that appear to be driven by electron interactions, including insulating states, superconductivity and magnetism3,4,5,6. Here we report electrical transport measurements up to room temperature for twist angles varying between 0.75° and 2°. We find that the resistivity, ρ, scales linearly with temperature, T, over a wide range of T before falling again owing to interband activation. The T-linear response is much larger than observed in monolayer graphene for all measured devices, and in particular increases by more than three orders of magnitude in the range where the flat band exists. Our results point to the dominant role of electron–phonon scattering in twisted bilayer graphene, with possible implications for the origin of the observed superconductivity.},
  author       = {Polshyn, Hryhoriy and Yankowitz, Matthew and Chen, Shaowen and Zhang, Yuxuan and Watanabe, K. and Taniguchi, T. and Dean, Cory R. and Young, Andrea F.},
  issn         = {1745-2481},
  journal      = {Nature Physics},
  keywords     = {general physics and astronomy},
  number       = {10},
  pages        = {1011--1016},
  publisher    = {Springer Nature},
  title        = {{Large linear-in-temperature resistivity in twisted bilayer graphene}},
  doi          = {10.1038/s41567-019-0596-3},
  volume       = {15},
  year         = {2019},
}

@article{10622,
  abstract     = {We demonstrate a method for manipulating small ensembles of vortices in multiply connected superconducting structures. A micron-size magnetic particle attached to the tip of a silicon cantilever is used to locally apply magnetic flux through the superconducting structure. By scanning the tip over the surface of the device and by utilizing the dynamical coupling between the vortices and the cantilever, a high-resolution spatial map of the different vortex configurations is obtained. Moving the tip to a particular location in the map stabilizes a distinct multivortex configuration. Thus, the scanning of the tip over a particular trajectory in space permits nontrivial operations to be performed, such as braiding of individual vortices within a larger vortex ensemble—a key capability required by many proposals for topological quantum computing.},
  author       = {Polshyn, Hryhoriy and Naibert, Tyler and Budakian, Raffi},
  issn         = {1530-6992},
  journal      = {Nano Letters},
  keywords     = {mechanical engineering, condensed matter physics, general materials science, general chemistry, bioengineering},
  number       = {8},
  pages        = {5476--5482},
  publisher    = {American Chemical Society},
  title        = {{Manipulating multivortex states in superconducting structures}},
  doi          = {10.1021/acs.nanolett.9b01983},
  volume       = {19},
  year         = {2019},
}

@article{10625,
  abstract     = {The discovery of superconductivity and exotic insulating phases in twisted bilayer graphene has established this material as a model system of strongly correlated electrons. To achieve superconductivity, the two layers of graphene need to be at a very precise angle with respect to each other. Yankowitz et al. now show that another experimental knob, hydrostatic pressure, can be used to tune the phase diagram of twisted bilayer graphene (see the Perspective by Feldman). Applying pressure increased the coupling between the layers, which shifted the superconducting transition to higher angles and somewhat higher temperatures.},
  author       = {Yankowitz, Matthew and Chen, Shaowen and Polshyn, Hryhoriy and Zhang, Yuxuan and Watanabe, K. and Taniguchi, T. and Graf, David and Young, Andrea F. and Dean, Cory R.},
  issn         = {1095-9203},
  journal      = {Science},
  keywords     = {multidisciplinary},
  number       = {6431},
  pages        = {1059--1064},
  publisher    = {American Association for the Advancement of Science (AAAS)},
  title        = {{Tuning superconductivity in twisted bilayer graphene}},
  doi          = {10.1126/science.aav1910},
  volume       = {363},
  year         = {2019},
}

@article{10664,
  abstract     = {Since the discovery of correlated insulators and superconductivity in magic-angle twisted bilayer graphene (tBLG) ([1, 2], JCCM April 2018), theorists have been excitedly pursuing the alluring mix of band topology, symmetry breaking, Mott insulators and superconductivity at play, as well as the potential relation (if any) to high-Tc physics. Now a new stream
of experimental work is arriving which further enriches the story. To briefly recap Episodes 1 and 2 (JCCM April and November 2018), when two graphene layers are stacked with a small rotational mismatch θ, the resulting long-wavelength moire pattern leads to a superlattice potential which reconstructs the low energy band structure. When θ approaches the “magic-angle” θM ∼ 1 ◦, the band structure features eight nearly-flat bands which fill when the electron number per moire unit cell, n/n0, lies between −4 < n/n0 < 4. The bands can be counted as 8 = 2 × 2 × 2: for each spin (2×) and valley (2×) characteristic of monolayergraphene, tBLG has has 2× flat bands which cross at mini-Dirac points.},
  author       = {Yankowitz, Mathew and Chen, Shaowen and Polshyn, Hryhoriy and Watanabe, K. and Taniguchi, T. and Graf, David and Young, Andrea F. and Dean, Cory R. and Sharpe, Aaron L. and Fox, E.J. and Barnard, A.W. and Finney, Joe},
  journal      = {Journal Club for Condensed Matter Physics},
  publisher    = {Simons Foundation ; University of California, Riverside},
  title        = {{New correlated phenomena in magic-angle twisted bilayer graphene/s}},
  doi          = {10.36471/jccm_february_2019_03},
  volume       = {03},
  year         = {2019},
}

@inproceedings{10722,
  abstract     = {Bilayer graphene, rotationally faulted to ~1.1 degree misalignment, has recently been shown to host superconducting and resistive states associated with the formation of a flat electronic band. While numerous theories exist for the origins of both states, direct validation of these theories remains an outstanding experimental problem. Here, we focus on the resistive states occurring at commensurate filling (1/2, 1/4, and 3/4) of the two lowest superlattice bands. We test theoretical proposals that these states arise due to broken spin—and/or valley—symmetry by performing direct magnetic imaging with nanoscale SQUID-on-tip microscopy. This technique provides single-spin resolved magnetometry on sub-100nm length scales. I will present imaging data from our 4.2K nSOT microscope on graphite-gated twisted bilayers near the flat band condition and discuss the implications for the physics of the commensurate resistive states.},
  author       = {Serlin, Marec and Tschirhart, Charles and Polshyn, Hryhoriy and Zhu, Jiacheng and Huber, Martin E. and Young, Andrea},
  booktitle    = {APS March Meeting 2019},
  issn         = {0003-0503},
  location     = {Boston, MA, United States},
  number       = {2},
  publisher    = {American Physical Society},
  title        = {{Direct Imaging of magnetic structure in twisted bilayer graphene with scanning nanoSQUID-On-Tip microscopy}},
  volume       = {64},
  year         = {2019},
}

@inproceedings{10723,
  abstract     = {In monolayer graphene, the interplay of electronic correlations with the internal spin- and valley- degrees of freedom leads to a complex phase diagram of isospin symmetry breaking at high magnetic fields. Recently, Wei et al. (Science (2018)) demonstrated that spin waves can be electrically generated and detected in graphene heterojunctions, allowing direct experiment access to the spin degree of freedom. Here, we apply this technique to high quality graphite-gated graphene devices showing robust fractional quantum Hall phases and isospin phase transitions. We use an edgeless Corbino geometry to eliminate the contributions of edge states to the spin-wave mediated nonlocal voltage, allowing unambiguous identification of spin wave transport signatures. Our data reveal two phases within the ν = 1 plateau. For exactly ν=1, charge is localized but spin waves propagate freely while small carrier doping completely quenches the low-energy spin-wave transport, even as those charges remain localized. We identify this new phase as a spin textured electron solid. We also find that spin-wave transport is modulated by phase transitions in the valley order that preserve spin polarization, suggesting that this technique is sensitive to both spin and valley order.},
  author       = {Zhou, Haoxin and Polshyn, Hryhoriy and Tanaguchi, Takashi and Watanabe, Kenji and Young, Andrea},
  booktitle    = {APS March Meeting 2019},
  issn         = {0003-0503},
  location     = {Boston, MA, United States},
  number       = {2},
  publisher    = {American Physical Society},
  title        = {{Spin wave transport through electron solids and fractional quantum Hall liquids in graphene}},
  volume       = {64},
  year         = {2019},
}

@inproceedings{10724,
  abstract     = {Twisted bilayer graphene (tBLG) near the flat band condition is a versatile new platform for the study of correlated physics in 2D. Resistive states have been observed at several commensurate fillings of the flat miniband, along with superconducting states near half filling. To better understand the electronic structure of this system, we study electronic transport of graphite gated superconducting tBLG devices in the normal regime. At high magnetic fields, we observe full lifting of the spin and valley degeneracy. The transitions in the splitting of this four-fold degeneracy as a function of carrier density indicate Landau level (LL) crossings, which tilted field measurements show occur between LLs with different valley polarization. Similar LL structure measured in two devices, one with twist angle θ=1.08° at ambient pressure and one at θ=1.27° and 1.33GPa, suggests that the dimensionless combination of twist angle and interlayer coupling controls the relevant details of the band structure. In addition, we find that the temperature dependence of the resistance at B=0 shows linear growth at several hundred Ohm/K in a broad range of temperatures. We discuss the implications for modeling the scattering processes in this system.},
  author       = {Polshyn, Hryhoriy and Zhang, Yuxuan and Yankowitz, Matthew and Chen, Shaowen and Taniguchi, Takashi and Watanabe, Kenji and Graf, David E. and Dean, Cory R. and Young, Andrea},
  booktitle    = {APS March Meeting 2019},
  issn         = {0003-0503},
  location     = {Boston, MA, United States},
  number       = {2},
  publisher    = {American Physical Society},
  title        = {{Normal state transport in superconducting twisted bilayer graphene}},
  volume       = {64},
  year         = {2019},
}

@inproceedings{10725,
  abstract     = {Bilayer graphene with ~ 1.1 degrees twist mismatch between the layers hosts a low energy flat band in which the Coulomb interaction is large relative to the bandwidth, promoting correlated insulating states at half band filling, and superconducting (SC) phases with dome-like structure neighboring correlated insulating states. Here we show measurements of a dual-graphite-gated twisted bilayer graphene device, which minimizes charge inhomogeneity. We observe new correlated phases, including for the first time a SC pocket near half-filling of the electron-doped band and resistive states at quarter-filling of both bands that emerge in a magnetic field. Changing the layer polarization with vertical electric field reveals an unexpected competition between SC and correlated insulator phases, which we interpret to result from differences in disorder of each graphene layer and underscores the spatial inhomogeneity like twist angle as a significant source of disorder in these devices [1].},
  author       = {Chen, Shaowen and Yankowitz, Matthew and Polshyn, Hryhoriy and Watanabe, Kenji and Taniguchi, Takashi and Graf, David E. and Young, Andrea and Dean, Cory R.},
  booktitle    = {APS March Meeting 2019},
  issn         = {0003-0503},
  location     = {Boston, MA, United States},
  number       = {2},
  publisher    = {American Physical Society},
  title        = {{Correlated insulating and superconducting phases in twisted bilayer graphene}},
  volume       = {64},
  year         = {2019},
}

@article{9460,
  abstract     = {Epigenetic reprogramming is required for proper regulation of gene expression in eukaryotic organisms. In Arabidopsis, active DNA demethylation is crucial for seed viability, pollen function, and successful reproduction. The DEMETER (DME) DNA glycosylase initiates localized DNA demethylation in vegetative and central cells, so-called companion cells that are adjacent to sperm and egg gametes, respectively. In rice, the central cell genome displays local DNA hypomethylation, suggesting that active DNA demethylation also occurs in rice; however, the enzyme responsible for this process is unknown. One candidate is the rice REPRESSOR OF SILENCING 1a (ROS1a) gene, which is related to DME and is essential for rice seed viability and pollen function. Here, we report genome-wide analyses of DNA methylation in wild-type and ros1a mutant sperm and vegetative cells. We find that the rice vegetative cell genome is locally hypomethylated compared with sperm by a process that requires ROS1a activity. We show that many ROS1a target sequences in the vegetative cell are hypomethylated in the rice central cell, suggesting that ROS1a also demethylates the central cell genome. Similar to Arabidopsis, we show that sperm non-CG methylation is indirectly promoted by DNA demethylation in the vegetative cell. These results reveal that DNA glycosylase-mediated DNA demethylation processes are conserved in Arabidopsis and rice, plant species that diverged 150 million years ago. Finally, although global non-CG methylation levels of sperm and egg differ, the maternal and paternal embryo genomes show similar non-CG methylation levels, suggesting that rice gamete genomes undergo dynamic DNA methylation reprogramming after cell fusion.},
  author       = {Kim, M. Yvonne and Ono, Akemi and Scholten, Stefan and Kinoshita, Tetsu and Zilberman, Daniel and Okamoto, Takashi and Fischer, Robert L.},
  issn         = {1091-6490},
  journal      = {Proceedings of the National Academy of Sciences},
  keywords     = {Multidisciplinary},
  number       = {19},
  pages        = {9652--9657},
  publisher    = {National Academy of Sciences},
  title        = {{DNA demethylation by ROS1a in rice vegetative cells promotes methylation in sperm}},
  doi          = {10.1073/pnas.1821435116},
  volume       = {116},
  year         = {2019},
}

@article{9530,
  abstract     = {Background
DNA methylation of active genes, also known as gene body methylation, is found in many animal and plant genomes. Despite this, the transcriptional and developmental role of such methylation remains poorly understood. Here, we explore the dynamic range of DNA methylation in honey bee, a model organism for gene body methylation.

Results
Our data show that CG methylation in gene bodies globally fluctuates during honey bee development. However, these changes cause no gene expression alterations. Intriguingly, despite the global alterations, tissue-specific CG methylation patterns of complete genes or exons are rare, implying robust maintenance of genic methylation during development. Additionally, we show that CG methylation maintenance fluctuates in somatic cells, while reaching maximum fidelity in sperm cells. Finally, unlike universally present CG methylation, we discovered non-CG methylation specifically in bee heads that resembles such methylation in mammalian brain tissue.

Conclusions
Based on these results, we propose that gene body CG methylation can oscillate during development if it is kept to a level adequate to preserve function. Additionally, our data suggest that heightened non-CG methylation is a conserved regulator of animal nervous systems.},
  author       = {Harris, Keith D. and Lloyd, James P. B. and Domb, Katherine and Zilberman, Daniel and Zemach, Assaf},
  issn         = {1756-8935},
  journal      = {Epigenetics and Chromatin},
  publisher    = {Springer Nature},
  title        = {{DNA methylation is maintained with high fidelity in the honey bee germline and exhibits global non-functional fluctuations during somatic development}},
  doi          = {10.1186/s13072-019-0307-4},
  volume       = {12},
  year         = {2019},
}

