Relationships between the structural and functional organization of the turtle cell nucleolus

Bartholomé, Odile; Franck, Claire; Piscicelli, Patricia; Lalun, Nathalie; Defourny, Jean; Renauld, Justine; Thelen, Nicolas; Lamaye, Françoise; Ploton, Dominique; Thiry, Marc

doi:10.1016/j.jsb.2019.09.015

Cited by 5 publications

(5 citation statements)

References 35 publications

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“…Nature reviews | Molecular cell Biology subcompartment emerged at the transition between anamniotes and amniotes, within the class Reptilia, and this tripartite organization has been retained in all modern eukaryotes inspected 33,34 . Mammalian cell nucleoli, which are by far the best studied, display three internal phase-separated subcompartments: the fibrillar centre (FC), the dense fibrillar component (DFC) and the granular component (GC).…”

Section: Non-equilibriummentioning

confidence: 99%

The nucleolus as a multiphase liquid condensate

Lafontaine

Riback

Bascetin

et al. 2020

Nat Rev Mol Cell Biol

702

592

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Among numerous microscopically visible nuclear substructures, the nucleolus is the most prominent and represents a functionally and biophysically distinct body or compartment. The nucleolus is, in fact, so prominent that it drew the attention of early biologists over 200 years ago, in light microscopy studies by Fontana, Valentin and Wagner 1. Following these early descriptions came the understanding of the functional importance of the nucleolus, including its primary role as the site for the initial steps of ribosome biogenesis, including RNA polymerase I (Pol I)-driven transcription, processing and modification of ribosomal RNA (rRNA) and the assembly of rRNA-containing complexes 2 (Fig. 1). These processes involve several hundred protein transacting factors and small nucleolar RNAs 3 , which serve to guide the specificity of rRNA chemical modifications, pre-rRNA folding and cleavage. Once precursor subunits are released from the nucleolar structure, they undergo further maturation in the nucleoplasm and cytoplasm prior to becoming fully functional ribosomal subunits, ready to engage in translating mRNA into protein. This nucleolar function is accompanied by organization of the nucleolus into distinct subcompartments. In mammalian cells, nucleoli display three layers, nested like Russian dolls, where successive steps of ribosome production take place, starting

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Section: Non-equilibriummentioning

confidence: 99%

The nucleolus as a multiphase liquid condensate

Lafontaine

Riback

Bascetin

et al. 2020

Nat Rev Mol Cell Biol

702

592

View full text Add to dashboard Cite

show abstract

“…This method is known to improve the contrast of the condensed chromatin within the cell nucleus [17], as formerly shown in another yeast, Candida albicans [18]. It also makes it possible to clearly distinguish the different constituents of the nucleolus [19].…”

Section: Resultsmentioning

confidence: 90%

“…It was proposed that such an organization in three nucleolar subcompartments is a recent evolutionary acquisition that emerged only after the transition between anamniote and amniote organisms [7,19,31]. According to this model, the yeast nucleolus displays only two subcompartments, fibrillar strands (F) and granules (G), with the strands corresponding to sites of active transcription of ribosomal DNA genes, and the granules to maturing precursor ribosomal particles.…”

Section: Two Types Of Dna Are Present In the Yeast Nucleolusmentioning

confidence: 99%

Visualization of Chromatin in the Yeast Nucleus and Nucleolus Using Hyperosmotic Shock

Thelen

Defourny

Lafontaine

et al. 2021

IJMS

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Unlike in most eukaryotic cells, the genetic information of budding yeast in the exponential growth phase is only present in the form of decondensed chromatin, a configuration that does not allow its visualization in cell nuclei conventionally prepared for transmission electron microscopy. In this work, we studied the distribution of chromatin and its relationships to the nucleolus using different cytochemical and immunocytological approaches applied to yeast cells subjected to hyperosmotic shock. Our results show that osmotic shock induces the formation of heterochromatin patches in the nucleoplasm and intranucleolar regions of the yeast nucleus. In the nucleolus, we further revealed the presence of osmotic shock-resistant DNA in the fibrillar cords which, in places, take on a pinnate appearance reminiscent of ribosomal genes in active transcription as observed after molecular spreading (“Christmas trees”). We also identified chromatin-associated granules whose size, composition and behaviour after osmotic shock are reminiscent of that of mammalian perichromatin granules. Altogether, these data reveal that it is possible to visualize heterochromatin in yeast and suggest that the yeast nucleus displays a less-effective compartmentalized organization than that of mammals.

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“…A wide range of microscopy techniques have been used in combination with dedicated staining methods to detect the nucleolus quantitatively in cultured cells and tissue biopsies. In principle, this requires either particular labeling chemistry, for example, silver nitrate-based AgNOR staining of the argyrophilic proteins which abound in the nucleolus (Bartholome et al, 2019 ; Ploton et al, 1986 ; Thelen et al, 2021 ), the use of specific antibodies for immunodetection, or expression of fluorescently tagged proteins for direct detection (Nicolas et al, 2016 ; Stamatopoulou et al, 2018 ; Stenstrom et al, 2020 ). More recently, super-resolution techniques have been applied to fixed and live samples, revealing the existence of additional nucleolar subphases (Ide et al, 2020 ; Yao et al, 2019 ).…”

Section: Introductionmentioning

confidence: 99%

Detecting material state changes in the nucleolus by label-free digital holographic microscopy

Zorbas,

Soenmez,

Léger

et al. 2024

EMBO Rep

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Ribosome biogenesis is initiated in the nucleolus, a multiphase biomolecular condensate formed by liquid-liquid phase separation. The nucleolus is a powerful disease biomarker and stress biosensor whose morphology reflects function. Here we have used digital holographic microscopy (DHM), a label-free quantitative phase contrast microscopy technique, to detect nucleoli in adherent and suspension human cells. We trained convolutional neural networks to detect and quantify nucleoli automatically on DHM images. Holograms containing cell optical thickness information allowed us to define a novel index which we used to distinguish nucleoli whose material state had been modulated optogenetically by blue-light-induced protein aggregation. Nucleoli whose function had been impacted by drug treatment or depletion of ribosomal proteins could also be distinguished. We explored the potential of the technology to detect other natural and pathological condensates, such as those formed upon overexpression of a mutant form of huntingtin, ataxin-3, or TDP-43, and also other cell assemblies (lipid droplets). We conclude that DHM is a powerful tool for quantitatively characterizing nucleoli and other cell assemblies, including their material state, without any staining.

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Relationships between the structural and functional organization of the turtle cell nucleolus

Cited by 5 publications

References 35 publications

The nucleolus as a multiphase liquid condensate

The nucleolus as a multiphase liquid condensate

Visualization of Chromatin in the Yeast Nucleus and Nucleolus Using Hyperosmotic Shock

Detecting material state changes in the nucleolus by label-free digital holographic microscopy

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