siRNA-Mediated BmAurora B Depletion Impedes the Formation of Holocentric Square Spindles in Silkworm Metaphase BmN4 Cells
Silkworm ovary-derived BmN4 cells rely on chromatin-induced spindle assembly to form microtubule-based square mitotic spindles that ensure accurate segregation of holocentric chromosomes during cell division. The chromosome passenger protein Aurora B regulates chromosomal condensation and segregatio...
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MDPI AG
2024-01-01
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| Series: | Insects |
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| author | Bing Zhang Camilo Ayra-Pardo Xiaoning Liu Meiting Song Dandan Li Yunchao Kan |
| author_facet | Bing Zhang Camilo Ayra-Pardo Xiaoning Liu Meiting Song Dandan Li Yunchao Kan |
| author_sort | Bing Zhang |
| collection | DOAJ |
| description | Silkworm ovary-derived BmN4 cells rely on chromatin-induced spindle assembly to form microtubule-based square mitotic spindles that ensure accurate segregation of holocentric chromosomes during cell division. The chromosome passenger protein Aurora B regulates chromosomal condensation and segregation, spindle assembly checkpoint activation, and cytokinesis; however, its role in holocentric organisms needs further clarification. This study examined the architecture and dynamics of spindle microtubules during prophase and metaphase in BmN4 cells and those with siRNA-mediated BmAurora B knockdown using immunofluorescence labeling. Anti-α-tubulin and anti-γ-tubulin antibodies revealed faint γ-tubulin signals colocalized with α-tubulin in early prophase during nuclear membrane rupture, which intensified as prophase progressed. At this stage, bright regions of α-tubulin around and on the nuclear membrane surrounding the chromatin suggested the start of microtubules assembling in the microtubule-organizing centers (MTOCs). In metaphase, fewer but larger γ-tubulin foci were detected on both sides of the chromosomes. This resulted in a distinctive multipolar square spindle with holocentric chromosomes aligned at the metaphase plate. siRNA-mediated BmAurora B knockdown significantly reduced the γ-tubulin foci during prophase, impacting microtubule nucleation and spindle structure in metaphase. Spatiotemporal <i>BmAurora B</i> expression analysis provided new insights into the regulation of this mitotic kinase in silkworm larval gonads during gametogenesis. Our results suggest that BmAurora B is crucial for the formation of multipolar square spindles in holocentric insects, possibly through the activation of γ-tubulin ring complexes in multiple centrosome-like MTOCs. |
| first_indexed | 2024-03-08T10:46:35Z |
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| institution | Directory Open Access Journal |
| issn | 2075-4450 |
| language | English |
| last_indexed | 2024-03-08T10:46:35Z |
| publishDate | 2024-01-01 |
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| series | Insects |
| spelling | doaj.art-be7e14eeb7964adf8d7f53567bf033032024-01-26T17:04:20ZengMDPI AGInsects2075-44502024-01-011517210.3390/insects15010072siRNA-Mediated BmAurora B Depletion Impedes the Formation of Holocentric Square Spindles in Silkworm Metaphase BmN4 CellsBing Zhang0Camilo Ayra-Pardo1Xiaoning Liu2Meiting Song3Dandan Li4Yunchao Kan5Henan Key Laboratory of Insect Biology in Funiu Mountain, Henan International Joint Laboratory of Insect Biology, College of Life Science and Agricultural Engineering, Nanyang Normal University, 1638 Wolong Road, Nanyang 473061, ChinaCIIMAR–Interdisciplinary Centre of Marine and Environmental Research, Terminal de Cruzeiros do Porto de Leixões, University of Porto, Avda. General Norton de Matos s/n, 4450-208 Matosinhos, PortugalHenan Key Laboratory of Insect Biology in Funiu Mountain, Henan International Joint Laboratory of Insect Biology, College of Life Science and Agricultural Engineering, Nanyang Normal University, 1638 Wolong Road, Nanyang 473061, ChinaHenan Key Laboratory of Insect Biology in Funiu Mountain, Henan International Joint Laboratory of Insect Biology, College of Life Science and Agricultural Engineering, Nanyang Normal University, 1638 Wolong Road, Nanyang 473061, ChinaHenan Key Laboratory of Insect Biology in Funiu Mountain, Henan International Joint Laboratory of Insect Biology, College of Life Science and Agricultural Engineering, Nanyang Normal University, 1638 Wolong Road, Nanyang 473061, ChinaHenan Key Laboratory of Insect Biology in Funiu Mountain, Henan International Joint Laboratory of Insect Biology, College of Life Science and Agricultural Engineering, Nanyang Normal University, 1638 Wolong Road, Nanyang 473061, ChinaSilkworm ovary-derived BmN4 cells rely on chromatin-induced spindle assembly to form microtubule-based square mitotic spindles that ensure accurate segregation of holocentric chromosomes during cell division. The chromosome passenger protein Aurora B regulates chromosomal condensation and segregation, spindle assembly checkpoint activation, and cytokinesis; however, its role in holocentric organisms needs further clarification. This study examined the architecture and dynamics of spindle microtubules during prophase and metaphase in BmN4 cells and those with siRNA-mediated BmAurora B knockdown using immunofluorescence labeling. Anti-α-tubulin and anti-γ-tubulin antibodies revealed faint γ-tubulin signals colocalized with α-tubulin in early prophase during nuclear membrane rupture, which intensified as prophase progressed. At this stage, bright regions of α-tubulin around and on the nuclear membrane surrounding the chromatin suggested the start of microtubules assembling in the microtubule-organizing centers (MTOCs). In metaphase, fewer but larger γ-tubulin foci were detected on both sides of the chromosomes. This resulted in a distinctive multipolar square spindle with holocentric chromosomes aligned at the metaphase plate. siRNA-mediated BmAurora B knockdown significantly reduced the γ-tubulin foci during prophase, impacting microtubule nucleation and spindle structure in metaphase. Spatiotemporal <i>BmAurora B</i> expression analysis provided new insights into the regulation of this mitotic kinase in silkworm larval gonads during gametogenesis. Our results suggest that BmAurora B is crucial for the formation of multipolar square spindles in holocentric insects, possibly through the activation of γ-tubulin ring complexes in multiple centrosome-like MTOCs.https://www.mdpi.com/2075-4450/15/1/72<i>Bombyx mori</i>chromatin-induced spindle assemblysiRNAcell divisionmitosis |
| spellingShingle | Bing Zhang Camilo Ayra-Pardo Xiaoning Liu Meiting Song Dandan Li Yunchao Kan siRNA-Mediated BmAurora B Depletion Impedes the Formation of Holocentric Square Spindles in Silkworm Metaphase BmN4 Cells Insects <i>Bombyx mori</i> chromatin-induced spindle assembly siRNA cell division mitosis |
| title | siRNA-Mediated BmAurora B Depletion Impedes the Formation of Holocentric Square Spindles in Silkworm Metaphase BmN4 Cells |
| title_full | siRNA-Mediated BmAurora B Depletion Impedes the Formation of Holocentric Square Spindles in Silkworm Metaphase BmN4 Cells |
| title_fullStr | siRNA-Mediated BmAurora B Depletion Impedes the Formation of Holocentric Square Spindles in Silkworm Metaphase BmN4 Cells |
| title_full_unstemmed | siRNA-Mediated BmAurora B Depletion Impedes the Formation of Holocentric Square Spindles in Silkworm Metaphase BmN4 Cells |
| title_short | siRNA-Mediated BmAurora B Depletion Impedes the Formation of Holocentric Square Spindles in Silkworm Metaphase BmN4 Cells |
| title_sort | sirna mediated bmaurora b depletion impedes the formation of holocentric square spindles in silkworm metaphase bmn4 cells |
| topic | <i>Bombyx mori</i> chromatin-induced spindle assembly siRNA cell division mitosis |
| url | https://www.mdpi.com/2075-4450/15/1/72 |
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