Positioning centrioles and centrosomes

The Journal of Cell Biology, Journal Year: 2024, Volume and Issue: 223(4)

Published: March 21, 2024

Centrosomes are the primary microtubule organizer in eukaryotic cells. In addition to shaping intracellular network and mitotic spindle, centrosomes responsible for positioning cilia flagella. To fulfill these diverse functions, must be properly located within cells, which requires that they undergo transport. Importantly, centrosome mispositioning has been linked ciliopathies, cancer, infertility. The mechanisms by migrate context dependent. many move via indirect motor transport, whereby centrosomal microtubules engage anchored proteins exert forces on those microtubules, resulting movement. However, some cases, direct or centriole functions as cargo directly binds molecular motors then walk stationary microtubules. this review, we summarize of motility consequences identify key questions remain addressed.

Language: Английский

---

Adaptive evolution of CENP-T modulates centromere binding

Current Biology, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 1, 2025

Language: Английский

---

How germ granules promote germ cell fate

Nature Reviews Genetics, Journal Year: 2024, Volume and Issue: 25(11), P. 803 - 821

Published: June 18, 2024

Language: Английский

---

OVO positively regulates essential maternal pathways by binding near the transcriptional start sites in the Drosophila female germline

eLife, Journal Year: 2024, Volume and Issue: 13

Published: Feb. 12, 2024

Differentiation of female germline stem cells into a mature oocyte includes the expression RNAs and proteins that drive early embryonic development in Drosophila . We have little insight what activates these maternal factors. One candidate is zinc-finger protein OVO. OVO required for viability has been shown to positively regulate its own expression, as well downstream target, ovarian tumor , by binding transcriptional start site (TSS). To find additional targets further elucidate OVO’s role development, we performed ChIP-seq determine genome-wide occupancy, RNA-seq comparing hypomorphic wild type rescue ovo alleles. preferentially binds close proximity target TSSs genome-wide, associated with open chromatin, transcriptionally active histone marks, OVO-dependent expression. Motif enrichment analysis on ChIP peaks identified 5’-TAACNGT-3’ DNA motif spatially enriched near TSSs. However, does not exhibit precise spacing relative TSS characteristic RNA polymerase II complex core promoter elements. Integrated genomics showed 525 genes are bound increase known be essential maternally expressed genes. These include involved anterior/posterior/germ plasm specification ( bcd, exu, swa, osk, nos, aub, pgc, gcl ), egg activation png, plu, gnu, wisp, C(3)g, mtrm translational regulation cup orb bru1, me31B vitelline membrane formation fs(1)N fs(1)M3 clos ). This suggests master regulator responsible structural components provided development.

Language: Английский

---

Chromatin and gene expression changes during female Drosophila germline stem cell development illuminate the biology of highly potent stem cells

eLife, Journal Year: 2023, Volume and Issue: 12

Published: Aug. 31, 2023

Highly potent animal stem cells either self renew or launch complex differentiation programs, using mechanisms that are only partly understood. Drosophila female germline (GSCs) perpetuate without change over evolutionary time and generate cystoblast daughters develop into nurse oocytes. Cystoblasts initiate by generating a transient syncytial state, the cyst, increasing pericentromeric H3K9me3 modification, actions likely to suppress transposable element activity. Relatively open GSC chromatin is further restricted Polycomb repression of testis somatic cell-expressed genes briefly active in early germ cells. Subsequently, Neijre/CBP Myc help upregulate growth reprogram metabolism altering mitochondrial transmembrane transport, gluconeogenesis, other processes. In all these respects resembles development totipotent zygote. We propose cell state was shaped need resist transposon activity timescales.

Language: Английский

---

Ovaries of Lumbricidae earthworms (Annelida, Crassiclitellata), from morphology to ultrastructure

The European Zoological Journal, Journal Year: 2025, Volume and Issue: 92(1), P. 97 - 122

Published: Jan. 13, 2025

Earthworm (Megadrili) ovaries are paired organs located usually in the XIII segment. So far, only their localization and general morphology well known. Light, fluorescence, electron microscopy analyses were carried out to describe ovary histology ultrastructure selected representatives of family Lumbricidae. We studied 12 species from six genera: Aporrectodea, Dendrobaena, Eisenia, Lumbricus, Octolasion, Proctodrilus. It was revealed that Lumbricidae tiny, leaf-like structures with one string consisting growing oocytes. Morphologically, can be divided into a proximal part (much wider attached septum) distal (more narrow containing oocytes form an egg at end ovary). Ovaries built germ cells united numerous syncytial cysts accompanied by somatic cells. Clustering interconnected via intercellular bridges poorly developed central cytoplasmic mass (reticular cytophore). According histological ultrastructural results, three zones. Zone I contains oogonia early-meiotic already cysts, which all develop synchronously. In zone II, enter diplotene lose synchrony; most probably, cell detaches given cyst, continues meiosis, gathers nutrients, grows, becomes oocyte, whereas rest do not grow become nurse III consists (vitellogenic) interconnecting enveloped follicular Such organization is known as "Dendrobaena" type. Although there minor differences between species, no found internal organization. Thus, it postulated characteristic lumbricids. Among earthworms, occur hormogastrids probably other families closely related

Language: Английский

---

Multinucleation as a buffer against gene expression noise in syncytial myofibres

The Journal of Physiology, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 25, 2025

Skeletal muscle fibres, or myofibres, are exceptional for their vast size and complex multinucleated structure. Formed by the fusion of individual myoblasts, these syncytial cells contain hundreds even thousands nuclei that collectively coordinate synthesis essential proteins, ensuring can grow, repair maintain strength (Hansson & Eftestol, 2023). With some fibres extending up to 42 cm in length achieving diameters exceeding 100 µm, myofibers possess a cellular volume approximately 4000 times greater than human oocyte et al., 2020a). This extraordinary scale, coupled with elongated, cylindrical-like morphology, raises fundamental question: Why has evolution selected multinucleation cells, what specific advantages does this structural arrangement confer? The predominant hypothesis argues facilitates expansion cytoplasmic myofibres. By adding nuclei, cell increases its DNA content, which turn provides enhanced biosynthetic regulatory capacity support high demands protein maintenance increase nuclear may drive enlargement cytoplasm, allowing myofibres achieve size. While explanation is compelling, scale functional suggest serve purposes beyond simply enabling expansion, including regulation spatial metabolic homeostasis. Importantly, not unique skeletal fibres. Comparisons other polyploid systems highlight intriguing parallels, suggesting broader significance adaptation. For instance, fungus Ashbya gossypii relies on extensive hyphal networks, require coordinated enzymatic activity across large distances (Mayer 2024). Similarly, binucleated hepatocytes sustain liver function (Darmasaputra 2024; Guidotti 2003), whereas osteoclasts efficiently secrete digestive enzymes resorb areas bone (Ono Nakashima, 2018). Additionally, maturation Drosophila oocytes supported surrounding nurse multiple copies genome. These directly transfer components, mRNA, proteins materials, during development. enables grow while circumventing limitations would likely arise from relying single set genomic such mononuclear (Spradling 2022). Together, examples illustrate how evolved as versatile strategy address challenges maintaining homeostasis functionally specialized cells. evolutionary emergence appears be convergent phenomenon, arising independently diverse taxa (Peterson Fox, 2021). convergence underscores adaptive advantages, increased scalability potential buffer stochastic fluctuations gene expression. Studying alongside uncover shared principles regulation, organization noise reduction, well lineage-specific adaptations tailored distinct biological demands. I propose only addresses logistical supporting but also serves critical mechanism mitigate fluctuations, commonly referred 'noise' Gene expression noise, variability transcription translation, results random mRNA levels (Raj van Oudenaarden, 2008; Sanchez Golding, 2013), disrupt function. In mononucleated significantly impair However, distribution transcriptional form decentralized network independent units. could averaging them out, stable consistent cell. proposed noise-buffering homeostasis, adaptation physiological stress. article will explore mathematical foundations hypothesis, examining might noise. It discuss implications biology experimental approaches investigate relationship between offering insights into aspect organization. Multinucleated like many centres volume, uniquely equipped against If each nucleus acts an unit, achieves cumulative reducing relative impact enhancing overall SNR. Therefore, distributed myonuclei suppress stabilizing manner single-nucleus cannot achieve. When small number molecules transcribed – at low rates mean level low, thus (σmRNA) becomes relatively compared mean. leads shows increases, decreases. inverse square-root dependence implies particularly prone production cause variations levels. words, distributing reduce expression, resulting more volume. Thus, decreases following 1/ N $\sqrt $ scaling. framework strengthens central opinion piece, total buffers out bursts, reliable production, contributing robustness Empirical evidence abundance, present challenge As result, genes adopt different strategies based susceptibility Comparative studies species, Saccharomyces cerevisiae, Mus musculus Homo sapiens, have shown most actually favour higher translation over (Hausser 2019). there exceptions, Escherichia coli, where encoding ribosomal exhibit both rates, rare, balance processes finely tuned gene's role sensitivity Low-abundance often tolerate because transient spikes sufficient functions, signalling Despite localized mechanisms control still presence within myofibre solution stability varying rates. One key factor half-life. Longer half-lives, assuming quality, stabilize pool available remains time without need continuous transcription. preventing rapid degradation, longer half-lives otherwise lead abundance. addition, localization plays minimizing myonuclear domains. Myonuclei strategically positioned along fibre localize mRNAs nearby regions, products translated close respective domains prevents becoming diluted degraded, occur if they were dispersed throughout concentrating discrete domains, optimize process, steady supply when needed. molecular diffusion cytoplasm introduces another layer stochasticity molecules, concentration 2020b), system. localizing effects local abundance caused diffusion, thereby likelihood degradation dilution. closer proximity transcribing myonucleus translational machinery, synthesis. it reduces risk shortages energy-efficient, solely thermal energy being effective short distances, active transport complement (Denes 2021; Pinheiro 2021), addressing demand rendering less discrete, discussed (Prasad Millay, Bagley 2023; Hansson Moreover, heterogeneity among further contributes compartmentalized (Dos Santos 2020; Kim Petrany 2020), same patterns reflecting roles regions control. genetic material donated newly fused stem existing resident divergent (Sun 2024), highlighting complexity provide organizing controlling stability, ensure efficient, robust, adaptable changing conditions. conclusion, concept offers compelling extends well-known scaling match Multinucleation help noise-reduction effect compartmentalization ensures fine-tuned regions. To test combination required. Single-nucleus imaging analysis using advanced techniques smFISH live-cell real-time influences variability. Mathematical modelling, incorporating parameters predict Genetic manipulations alter state direct stability. types, certain fungi, offer regulating exploring inter-nuclear communication synchronize computational determine whether reduction indeed driving force behind systems, significant engineering, development, disease. Please note: publisher responsible content functionality any information supplied authors. Any queries (other missing content) should directed corresponding author article. None declared. K.-A.H.: Conception design work, drafting work revising critically important intellectual final approval version published agreement accountable all aspects work. None.

Language: Английский

---

Intense oocyte competition builds the female reproductive reserve in mice

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 31, 2025

Abstract During the process of ovariogenesis, more than two-thirds germ cells are sacrificed to enhance quality remaining oocytes. But detail selection is not completely understood in mammals. Here, by creating a high resolution 4- dimensional ovariogenesis imaging system, we recorded progress oocyte fate determination live mouse ovaries, and discovered an competition mechanism that determines survival We found dominant oocytes catch absorb cell debris from enrich their cytoplasm for survival. Single-cell sequencing demonstrated this follows classic autophagy- driven model. Blocking suppressing autophagy resulted enlarged pool survived However, these lacking were unable fully develop contribute fertility. Our study suggests mammals have evolved unique intensive system quality, necessary support long reproductive lifespan.

Language: Английский

---

Intercellular bridges are essential for transposon repression and meiosis in the male germline

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: Feb. 10, 2025

Language: Английский

---

Complementary Volume Electron Microscopy-based approaches reveal ultrastructural changes in germline intercellular bridges of D. melanogaster

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 23, 2025

ABSTRACT Intercellular bridges are essential to connect developing germline cells. The Drosophila melanogaster egg chamber is a powerful model system study intercellular bridges, or ring canals (RCs). RCs the oocyte supporting nurse cells, and defects in their stability growth lead infertility. Despite importance, it has been technically difficult use electron microscopy-based approaches monitor changes RC structure during oogenesis. Here, we describe application of complementary set volume EM-based visualize ultrastructural RCs. combination array tomography (AT) focused ion beam (FIB) scanning microscopy (SEM) allowed us gain insight into previously unappreciated aspects structure. We were able quantify differences size thickness within between germ cell clusters at different developmental stages. Within cluster, correlates with lineage; largest formed first division, smallest fourth mitotic division. observed formation membrane interdigitations vicinity much earlier than reported, reconstruction from mid-stage EC provided 3D orientation these extensive cell-cell contacts. Our imaging also revealed novel that appeared line interior lumen. Although focus was on RCs, our dataset contains valuable details additional types structures, including fusome, stem cells niche, migrating border This framework could be applied other tissues samples face similar technical challenges, where small interest located large sample volume.

Language: Английский

---