Cell Cycle Regulation

Drosophila researchers met in sunny San Diego for the 49th annual meeting of The Genetics Society of America. It was cold outside and even colder inside. Like last year, ‘Mitosis, Meiosis and Cell Division’ was no longer a session. Instead, we searched out and covered talks and posters in ‘Cell Division and Growth Control’, ‘Gametogenesis’, ‘Cytoskeleton and Cell Biology’ and ‘Genome and Chromosome Structure’. We split up for maximal coverage and re-grouped later for the Workshop on Cell Cycle and Checkpoints. We apologize in advance for the brevity or omission of some reports.     

Retracted Manuscript: The WNT-5a derived peptide,Foxy-5, possesses dual properties that impair progression of ERα negative breast cancer

Retraction for: “The WNT-5a derived peptide, Foxy-5, possesses dual properties that impair progression of ERa negative breast cancer,” by Caroline E. Ford, Elin J. Ekström, Jillian Howlin and Tommy Andersson, which appeared in the June 15, 2009 issue of Cell Cycle (Ford CE, et al. Cell Cycle 2009; 8:1838-1842; 10.4161/cc.8.12.8863). The authors wish to note the following: “Recently a paper, on which I was the senior author and that was published in the Proceedings of the National Academy of Sciences titled “Wnt-5a signaling restores tamoxifen sensitivity in estrogen receptor-negative breast cancer cells” (Ford CE, Ekström EJ, Andersson T. Proc Natl Acad Sci USA 2009; 106:3919-24) was retracted. The fact that this paper was the direct reason for our review article in the Cell Cycle journal makes it logical that I also retract the cited review article published in the Cell Cycle journal, the other authors approve this retraction. We apologize for any inconvenience this may have caused.”     

A cell type annotation Jamboree—Revival of а communal science forum

Cell Atlases are currently being constructed for human tissues as well as several model organisms. New technologies make creation of vast datasets in many species possible, but the value of such data crucially depends on the quality of annotation. The tools of annotating single cell data and creating knowledge representations comparable across organisms have been lagging. We argue that successfully creating Cell Atlases will require a revival of a boot‐camp style forum for communal annotation combined with an intensive learning workshop, dubbed a “Jamboree”. We report on our experience of successfully developing a structure and curriculum and running such a Jamboree for Xenopus Embryonic Cell Types at the Janelia Farms campus of the Howard Hughes Medical Institute.     

Single-cell microliter-droplet screening system (MISS Cell): An integrated platform for automated high-throughput microbial monoclonal cultivation and picking

Solid plates have been used for microbial monoclonal isolation, cultivation, and colony picking since 1881. However, the process is labor- and resource-intensive for high-throughput requirements. Currently, several instruments have been integrated for automated and high-throughput picking, but complicated and expensive. To address these issues, we report a novel integrated platform, the single-cell microliter-droplet screening system (MISS Cell), for automated, high-throughput microbial monoclonal colony cultivation and picking. We verified the monoclonality of droplet cultures in the MISS Cell and characterized culture performance. Compared with solid plates, the MISS Cell generated a larger number of monoclonal colonies with higher initial growth rates using fewer resources. Finally, we established a workflow for automated high-throughput screening of Corynebacterium glutamicum using the MISS Cell and identified high glutamate-producing strains. The MISS Cell can serve as a universal platform to efficiently produce monoclonal colonies in high-throughput applications, overcoming the limitations of solid plates to promote rapid development in biotechnology.     

Predicting cell health phenotypes using image-based morphology profiling

Genetic and chemical perturbations impact diverse cellular phenotypes, including multiple indicators of cell health. These readouts reveal toxicity and antitumorigenic effects relevant to drug discovery and personalized medicine. We developed two customized microscopy assays, one using four targeted reagents and the other three targeted reagents, to collectively measure 70 specific cell health phenotypes including proliferation, apoptosis, reactive oxygen species, DNA damage, and cell cycle stage. We then tested an approach to predict multiple cell health phenotypes using Cell Painting, an inexpensive and scalable image-based morphology assay. In matched CRISPR perturbations of three cancer cell lines, we collected both Cell Painting and cell health data. We found that simple machine learning algorithms can predict many cell health readouts directly from Cell Painting images, at less than half the cost. We hypothesized that these models can be applied to accurately predict cell health assay outcomes for any future or existing Cell Painting dataset. For Cell Painting images from a set of 1500+ compound perturbations across multiple doses, we validated predictions by orthogonal assay readouts. We provide a web app to browse predictions: http://broad.io/cell-health-app. Our approach can be used to add cell health annotations to Cell Painting datasets.     

Targeting gene-virotherapy of cancer

Due to concerns regarding the overlapping figures in this review that are identical to those contained in a reviewarticle that we have co-authored and published earlier,we retract the above paper we published in Cell Research.Weapologize for any confusion that may be caused by this matter,although we stand by the scientific contents containedin the Cell Research paper.     

Requirments for primary human hepatocyte

‘Requirements for Primary Human Hepatocyte’ is the first set of guidelines on Primary Human Hepatocyte in China, jointly drafted and agreed upon by experts from the Chinese Society for Stem Cell Research. This standard specifies the technical requirements, test methods, test regulations, instructions for use, labelling requirements, packaging requirements, storage requirements and transportation requirements for Primary Human Hepatocyte, which is applicable to the quality control for Primary Human Hepatocyte. It was originally released by the China Society for Cell Biology on 9 January 2021. We hope that publication of these guidelines will promote institutional establishment, acceptance and execution of proper protocols and accelerate the international standardization of Primary Human Hepatocyte for applications.     

Requirements for human embryonic stem cells

‘Requirements for Human Embryonic Stem Cells’ is the first set of guidelines on human embryonic stem cells in China, jointly drafted and agreed upon by experts from the Chinese Society for Stem Cell Research. This standard specifies the technical requirements, test methods, test regulations, instructions for use, labelling requirements, packaging requirements, storage requirements and transportation requirements for human embryonic stem cells, which is applicable to the quality control for human embryonic stem cells. It was originally released by the China Society for Cell Biology on 26 February 2019 and was further revised on 30 April 2020. We hope that publication of these guidelines will promote institutional establishment, acceptance and execution of proper protocols, and accelerate the international standardization of human embryonic stem cells for applications.     

以TBL为导向的教学方法在“细胞分化、衰老与死亡”章节中的应用

以2011级大学新生为研究对象,在细胞生物学的＂细胞分化、衰老与死亡＂章节中采用TBL教学方法,通过对学生的基本情况（包括地域、中学的生物学基础等）、TBL教学团队的任务和评价来综合反映团队学习的效果。结果显示,TBL教学方法对《医学细胞生物学》的教学是有促进作用的,体现在学生利用课余时间查阅了资料、提出了问题,并尝试通过团队交流解决问题等。     

Osteogenin inhibits proliferation and stimulates differentiation in mouse osteoblast-like cells (MC3T3-E1)

Osteogenin, a novel bone differentiation factor, was recently purified and characterized. We examined its effect on the proliferation and differentiation of MC3T3-E1 osteoblast-like cells. Cell proliferation was inhibited the first 48 h after addition of osteogenin, and this effect was independent of serum. Osteogenin did not influence the cell morphology. Alkaline phosphatase promptly increased in a dose and time-dependent manner and appeared to be specific. Treatment with TGF-beta 1 resulted in inhibition of alkaline phosphatase activity, and was reversed by osteogenin within 48 h. Cell cultures treated with osteogenin for 72 h after confluence became responsive to parathyroid hormone. Synthesis of collagenous proteins was stimulated by osteogenin. The present results demonstrate a significant influence of osteogenin on the differentiation of osteogenic phenotype in MC3T3-E1 cells in vitro.     

Requirements for human cardiomyocytes

‘Requirements for human cardiomyocytes'', jointly drafted and agreed upon by experts from the Chinese Society for Stem Cell Research, is the first guideline for human cardiomyocytes in China. This standard specifies the technical requirements, test methods, test regulations, instructions for use, labelling requirements, packing requirements, storage requirements, transportation requirements and waste disposal requirements for human cardiomyocytes, which is designed to normalize and standardize human cardiomyocyte research and production. It was originally released by the China Society for Cell Biology on 9 January 2021. We hope that the publication of this guideline will promote institutional establishment, acceptance and execution of proper protocols, and accelerate the international standardization of human cardiomyocytes for applications.     

Extracellular roles for the molecular chaperone,hsp90

In an Extra Views publication by Eustace and Jay (Cell Cycle 2004; 3:1096-1098), we reported that the co-chaperone Hsp70 was not found in the conditioned media of HT-1080 fibrosarcoma cells grown in culture (Figure 1). We have since discovered that this finding is in error. We reproducibly observe Hsp70 in HT-1080 conditioned media and believe the previous result was flawed due to a poor batch of antibody used for immunoblotting. We sincerely apologize for any confusion that this error might have caused.     

Single Cell Genomics meeting in Stockholm: from single cells to cell types

A report on the second Single Cell Genomics conference held in Stockholm, Sweden, September 9–11, 2014.The second Single Cell Genomics conference was held in Stockholm and hosted by the Karolinska Institute. The ‘Venice of the North’ was the setting for an exciting and intense meeting, with scientists from very different disciplines tackling the numerous challenges that single cell genomics presents.During three days, 35 talks and more than 60 posters addressed many aspects of single cell genomics, from new experimental techniques to computational strategies for data analysis. We report on some of the main themes that emerged and, in our opinion, best illustrate the progress made and the new directions being undertaken by the field.     

FGF and EGF act synergistically to induce proliferation in BC3H1 myoblasts

BC3H1 muscle cells proliferate when grown in high concentrations of FBS (20%). Lowering the FBS concentration to 0.5% causes the cells to stop proliferating and is permissive for the morphological and biochemical differentiation of BC3H1 cells. Exposure of differentiated BC3H1 myocytes to high concentrations of serum or to the purified growth factors FGF or TGF-b induced a shutdown of this differentiation program but did not induce cell proliferation (Olson et al., J. Cell Biol., 103:1799-1805, 1986; Lathrop et al., J. Cell Biol., 100:1540-1547, 1985, and J. Cell Biol., 101:2194-2198, 1985). We explored the possibility that BC3H1 cells require factors to act synergistically to induce proliferation. We found that EGF and FGF function in a synergistic fashion to stimulate BC3H1 proliferation. Moreover, the temporal requirement for these growth factors suggest that they are functioning as competence and progression factors for BC3H1 cell proliferation.     

多维立体教学在细胞工程中的应用与实践

为提升工科专业课程教学质量,以成长记录袋课堂评价体系为基础,将多维立体教学法引入到高等院校生物类专业课程细胞工程的教学改革中,对课程的知识体系、施教形式、实施方案等开展了探索与实践。授课教师通过结合线上教学、互动教学、案例教学等多种教学模式的改革,不仅让生物工程专业的学生掌握了细胞工程的相关专业知识及科技前沿,更增强了学生的学习兴趣与积极性,提高了学生分析、解决与细胞工程相关的专业问题的能力,整体执行效果较好。本课程教学改革的实施,可为高校同类性质的其他专业课程提供借鉴与参考。     

General requirements for stem cells

The standard ‘General requirements for stem cells’ is the first set of general guidelines for stem cell research and production in China, jointly drafted and agreed upon by experts from the Chinese Society for Stem Cell Research. This standard specifies the classification, ethical requirements, quality requirements, quality control requirements, detection control requirements and waste disposal requirements of stem cells, which is applicable to stem cell research and production. It was firstly released by the Chinese Society for Cell Biology on 1 August 2017 and was further revised on 30 April 2020. We hope that publication of these guidelines will promote institutional establishment, acceptance, and execution of proper protocols, and accelerate the international standardization of stem cells for clinical development and therapeutic applications.     

Virtual NEURON: a strategy for merged biochemical and electrophysiological modeling

Because of its highly branched dendrite, the Purkinje neuron requires significant computational resources if coupled electrical and biochemical activity are to be simulated. To address this challenge, we developed a scheme for reducing the geometric complexity; while preserving the essential features of activity in both the soma and a remote dendritic spine. We merged our previously published biochemical model of calcium dynamics and lipid signaling in the Purkinje neuron, developed in the Virtual Cell modeling and simulation environment, with an electrophysiological model based on a Purkinje neuron model available in NEURON. A novel reduction method was applied to the Purkinje neuron geometry to obtain a model with fewer compartments that is tractable in Virtual Cell. Most of the dendritic tree was subject to reduction, but we retained the neuron’s explicit electrical and geometric features along a specified path from spine to soma. Further, unlike previous simplification methods, the dendrites that branch off along the preserved explicit path are retained as reduced branches. We conserved axial resistivity and adjusted passive properties and active channel conductances for the reduction in surface area, and cytosolic calcium for the reduction in volume. Rallpacks are used to validate the reduction algorithm and show that it can be generalized to other complex neuronal geometries. For the Purkinje cell, we found that current injections at the soma were able to produce similar trains of action potentials and membrane potential propagation in the full and reduced models in NEURON; the reduced model produces identical spiking patterns in NEURON and Virtual Cell. Importantly, our reduced model can simulate communication between the soma and a distal spine; an alpha function applied at the spine to represent synaptic stimulation gave similar results in the full and reduced models for potential changes associated with both the spine and the soma. Finally, we combined phosphoinositol signaling and electrophysiology in the reduced model in Virtual Cell. Thus, a strategy has been developed to combine electrophysiology and biochemistry as a step toward merging neuronal and systems biology modeling.     

Eukaryotic cells and their cell bodies: Cell Theory revised

BACKGROUND: Cell Theory, also known as cell doctrine, states that all eukaryotic organisms are composed of cells, and that cells are the smallest independent units of life. This Cell Theory has been influential in shaping the biological sciences ever since, in 1838/1839, the botanist Matthias Schleiden and the zoologist Theodore Schwann stated the principle that cells represent the elements from which all plant and animal tissues are constructed. Some 20 years later, in a famous aphorism Omnis cellula e cellula, Rudolf Virchow annunciated that all cells arise only from pre-existing cells. General acceptance of Cell Theory was finally possible only when the cellular nature of brain tissues was confirmed at the end of the 20th century. Cell Theory then rapidly turned into a more dogmatic cell doctrine, and in this form survives up to the present day. In its current version, however, the generalized Cell Theory developed for both animals and plants is unable to accommodate the supracellular nature of higher plants, which is founded upon a super-symplasm of interconnected cells into which is woven apoplasm, symplasm and super-apoplasm. Furthermore, there are numerous examples of multinucleate coenocytes and syncytia found throughout the eukaryote superkingdom posing serious problems for the current version of Cell Theory. SCOPE: To cope with these problems, we here review data which conform to the original proposal of Daniel Mazia that the eukaryotic cell is composed of an elemental Cell Body whose structure is smaller than the cell and which is endowed with all the basic attributes of a living entity. A complement to the Cell Body is the Cell Periphery Apparatus, which consists of the plasma membrane associated with other periphery structures. Importantly, boundary structures of the Cell Periphery Apparatus, although capable of some self-assembly, are largely produced and maintained by Cell Body activities and can be produced from it de novo. These boundary structures serve not only as mechanical support for the Cell Bodies but they also protect them from the hostile external environment and from inappropriate interactions with adjacent Cell Bodies within the organism. CONCLUSIONS: From the evolutionary perspective, Cell Bodies of eukaryotes are proposed to represent vestiges of hypothetical, tubulin-based 'guest' proto-cells. After penetrating the equally hypothetical actin-based 'host' proto-cells, tubulin-based 'guests' became specialized for transcribing, storing and partitioning DNA molecules via the organization of microtubules. The Cell Periphery Apparatus, on the other hand, represents vestiges of the actin-based 'host' proto-cells which have become specialized for Cell Body protection, shape control, motility and for actin-mediated signalling across the plasma membrane.     

Cytochemical localization of alkaline phosphatase in the cell membrane ofDictyostelium discoideum amebae

Histochemistry and Cell Biology - We demonstrated that alkaline phosphatase was localized on the cell membrane ofDictyostelium discoideum amebae and on isolated plasma membranes. The enzyme...