High-throughput gene screen reveals modulators of nuclear shape

Tamashunas, Andrew C; Tocco, Vincent J.; Matthews, James H.; Zhang, Qiao; Atanasova, Kalina R.; Paschall, Lauren; Pathak, Shreya; Ratnayake, Ranjala; Stephens, Andrew D.; Luesch, Hendrik; Licht, Jonathan D.; Lele, Tanmay P.

doi:10.1091/mbc.e19-09-0520

Cited by 35 publications

(40 citation statements)

References 60 publications

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“…Our data show that HP1α is one of the likely many possible chromatin crosslinking elements in the genome. There is a growing list of chromatin proteins and nuclear components contributing to maintenance of nuclear morphology, some of which have been identified by a genetic screen for effects on nuclear morphology ( Tamashunas et al, 2020 ) and a variety of other experiments (reviewed in Stephens et al, 2019a ). Other chromatin crosslinkers to be investigated include chromatin looping proteins and other components implicated by various experiments, such as cohesin, CTCF, mediator, and possibly RNA.…”

Section: Discussionmentioning

confidence: 99%

“…These changes in chromatin-based nuclear mechanics can, independently of lamins, cause abnormal nuclear morphology, which is a hallmark of human disease (Stephens et al, 2019a). A recent high-throughput screen revealed that many key chromatin proteins also contribute to nuclear shape (Tamashunas et al, 2020), raising the question of the relative roles of histone modifications versus chromatin proteins such as HP1α. Recent experimental and modeling studies suggest chromatin proteins, like HP1α, may contribute to mechanics by acting as physical linkers.…”

Section: Introductionmentioning

confidence: 99%

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HP1α is a chromatin crosslinker that controls nuclear and mitotic chromosome mechanics

Strom

Biggs

Banigan

et al. 2021

eLife

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Chromatin, which consists of DNA and associated proteins, contains genetic information and is a mechanical component of the nucleus. Heterochromatic histone methylation controls nucleus and chromosome stiffness, but the contribution of heterochromatin protein HP1α (CBX5) is unknown. We used a novel HP1α auxin-inducible degron human cell line to rapidly degrade HP1α. Degradation did not alter transcription, local chromatin compaction, or histone methylation, but did decrease chromatin stiffness. Single-nucleus micromanipulation reveals that HP1α is essential to chromatin-based mechanics and maintains nuclear morphology, separate from histone methylation. Further experiments with dimerization-deficient HP1αI165E indicate that chromatin crosslinking via HP1α dimerization is critical, while polymer simulations demonstrate the importance of chromatin-chromatin crosslinkers in mechanics. In mitotic chromosomes, HP1α similarly bolsters stiffness while aiding in mitotic alignment and faithful segregation. HP1α is therefore a critical chromatin-crosslinking protein that provides mechanical strength to chromosomes and the nucleus throughout the cell cycle and supports cellular functions.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

HP1α is a chromatin crosslinker that controls nuclear and mitotic chromosome mechanics

Strom

Biggs

Banigan

et al. 2021

eLife

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“…In a similar way, deviations from control values in nuclear geometrical descriptors, i.e ., major and minor axes (Fig. 4D), might indicate deformations and irregularities due to altered cytoskeleton or chromatin regulation [52]. LiveCellMiner automatically detects interphase to prophase and metaphase to anaphase transitions as well as the degree of rotation of the chromatin mass (Fig.…”

Section: Resultsmentioning

confidence: 99%

LiveCellMiner: A New Tool to Analyze Mitotic Progression

Moreno-Andrés

Bhattacharyya

Scheufen

et al. 2021

Preprint

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Live-cell imaging has become state of the art to accurately identify the nature of mitotic and cell cycle defects. Low- and high-throughput microscopy setups have yield huge data amounts of cells recorded in different experimental and pathological conditions. Tailored semi-automated and automated image analysis approaches allow the analysis of high-content screening data sets, saving time and avoiding bias. However, they were mostly designed for very specific experimental setups, which restricts their flexibility and usability. The general need for dedicated experiment-specific user-annotated training sets and experiment-specific user-defined segmentation parameters remains a major bottleneck for fully automating the analysis process. In this work we present LiveCellMiner, a highly flexible open-source software tool to automatically extract, analyze and visualize both aggregated and time-resolved image features with potential biological relevance. The software tool allows analysis across high-content data sets obtained in different platforms, in a quantitative and unbiased manner. As proof of principle application, we analyze here the dynamic chromatin and tubulin cytoskeleton features in human cells passing through mitosis highlighting the versatile and flexible potential of this tool set.

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“…In addition, the depletion of certain cytoskeletal-associated proteins [80, [114][115][116][117][118], the transcription factor GATA6 [119], the ER-localized LEM protein, ANKLE2 [63], and the SPANX cancer/testis antigen [122] each led to altered nuclear appearance. This list is not meant to be all-inclusive and other publications have identified additional proteins that regulate nuclear morphology [109,213,214]. While many proteins in Table 1 directly impact the structure of the nuclear envelope or lamina (e.g., lamins, LEM proteins), several of the listed proteins affect nuclear morphology indirectly.…”

Section: Mechanisms Of Alterations In Nuclear Morphologymentioning

confidence: 99%

Nuclear Dynamics and Chromatin Structure: Implications for Pancreatic Cancer

Flores

Tader

Tolosa

et al. 2021

Cells

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Changes in nuclear shape have been extensively associated with the dynamics and functionality of cancer cells. In most normal cells, nuclei have a regular ellipsoid shape and minimal variation in nuclear size; however, an irregular nuclear contour and abnormal nuclear size is often observed in cancer, including pancreatic cancer. Furthermore, alterations in nuclear morphology have become the ‘gold standard’ for tumor staging and grading. Beyond the utility of altered nuclear morphology as a diagnostic tool in cancer, the implications of altered nuclear structure for the biology and behavior of cancer cells are profound as changes in nuclear morphology could impact cellular responses to physical strain, adaptation during migration, chromatin organization, and gene expression. Here, we aim to highlight and discuss the factors that regulate nuclear dynamics and their implications for pancreatic cancer biology.

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High-throughput gene screen reveals modulators of nuclear shape

Abstract: Using a high-throughput RNAi screen of epigenetic regulators combined with an automated elliptical Fourier analysis, we identify genes required for the maintenance of nuclear shape in breast epithelial cells.

Cited by 35 publications

References 60 publications

HP1α is a chromatin crosslinker that controls nuclear and mitotic chromosome mechanics

HP1α is a chromatin crosslinker that controls nuclear and mitotic chromosome mechanics

LiveCellMiner: A New Tool to Analyze Mitotic Progression

Nuclear Dynamics and Chromatin Structure: Implications for Pancreatic Cancer

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