bims-micesi 2023-10-08 papers

bims-micesi

Biomed News

on Mitotic cell signalling

Issue of 2023–10–08
nine papers selected by
Valentina Piano, Uniklinik Köln

Chromosome biorientation requires Aurora B's spatial separation from its outer kinetochore substrates, but not its turnover at kinetochores.
Sgo1 interacts with CENP-A to guide accurate chromosome segregation in mitosis.
Genome-wide identification of mammalian cell-cycle invariant and mitotic-specific macroH2A1 domains.
Safeguarding transcriptional memory: a mitotic bookmarking role for chromatin remodelers.
Functional plasticity in chromosome-microtubule coupling on the evolutionary time scale.
CIP2A coordinates phosphosignaling, mitosis, and the DNA damage response.
Spindle assembly checkpoint insensitivity allows meiosis-II despite chromosomal defects in aged eggs.
Mitotic Errors Increase Radiation Sensitivity in Multiple Cancer Cell Types and in Laryngeal Cancer Patients.
Biallelic MAD2L1BP (p31comet) mutation is associated with mosaic aneuploidy and juvenile granulosa cell tumors.

Curr Biol. 2023 Sep 28. pii: S0960-9822(23)01219-8. [Epub ahead of print]

Chromosome biorientation requires Aurora B's spatial separation from its outer kinetochore substrates, but not its turnover at kinetochores.

Shuyu Li, Luis J Garcia-Rodriguez, Tomoyuki U Tanaka.

  For correct chromosome segregation in mitosis, sister kinetochores must interact with microtubules from opposite spindle poles (biorientation). For this, aberrant kinetochore-microtubule interaction must be resolved (error correction) by Aurora B kinase. Once biorientation is formed, tension is applied on kinetochore-microtubule interaction, stabilizing this interaction. The mechanism for this tension-dependent process has been debated. Here, we study how Aurora B localizations at different kinetochore sites affect the biorientation establishment and maintenance in budding yeast. Without the physiological Aurora B-INCENP recruitment mechanisms, engineered recruitment of Aurora B-INCENP to the inner kinetochore, but not to the outer kinetochore, prior to biorientation supports the subsequent biorientation establishment. Moreover, when the physiological Aurora B-INCENP recruitment mechanisms are present, an engineered Aurora B-INCENP recruitment to the outer kinetochore, but not to the inner kinetochore, during metaphase (after biorientation establishment) disrupts biorientation, which is dependent on the Aurora B kinase activity. These results suggest that the spatial separation of Aurora B from its outer kinetochore substrates is required to stabilize kinetochore-microtubule interaction when biorientation is formed and tension is applied on this interaction. Meanwhile, Aurora B exhibits dynamic turnover on the centromere/kinetochore during early mitosis, a process thought to be crucial for error correction and biorientation. However, using the engineered Aurora B-INCENP recruitment to the inner kinetochore, we demonstrate that, even without such a turnover, Aurora B-INCENP can efficiently support biorientation. Our study provides important insights into how Aurora B promotes error correction for biorientation in a tension-dependent manner.

Keywords:  Aurora B; Ipl1; budding yeast; chromosome biorientation; chromosome segregation; error correction; kinetochore; microtubule; mitosis; tension

DOI:  https://doi.org/10.1016/j.cub.2023.09.006
J Mol Cell Biol. 2023 Sep 30. pii: mjad061. [Epub ahead of print]

Sgo1 interacts with CENP-A to guide accurate chromosome segregation in mitosis.

Fengge Wu, Hameed Akbar, Chunyue Wang, Xiao Yuan, Zhen Dou, McKay Mullen, Liwen Niu, Liang Zhang, Jianye Zang, Zhikai Wang, Xuebiao Yao, Xiaoyu Song, Xing Liu.

  Shugoshin-1 (Sgo1) is necessary for maintaining sister centromere cohesion and ensuring accurate chromosome segregation during mitosis. It has been reported that the localization of Sgo1 at the centromere is dependent on Bub1-mediated phosphorylation of histone H2A at T120. However, it remains uncertain whether other centromeric proteins play a role in regulating the localization and function of Sgo1 during mitosis. Here, we show that CENP-A interacts with Sgo1 and determines the localization of Sgo1 to the centromere during mitosis. Further biochemical characterization revealed that lysine and arginine residues in the C-terminal domain of Sgo1 are critical for binding CENP-A. Interestingly, the replacement of these basic amino acids with acidic amino acids perturbed the localization of Sgo1 and Aurora B to the centromere, resulting in aberrant chromosome segregation and premature chromatid separation. Taken together, these findings reveal a previously unrecognized but direct link between Sgo1 and CENP-A in centromere plasticity control and illustrate how the Sgo1-CENP-A interaction guides accurate cell division.

Keywords:  Aurora B; CENP-A; Sgo1; centromere; kinetochore; mitosis

DOI:  https://doi.org/10.1093/jmcb/mjad061
Biosci Trends. 2023 Sep 29.

Genome-wide identification of mammalian cell-cycle invariant and mitotic-specific macroH2A1 domains.

Le Zhang, Bishan Ye, Zeqian Xu, Xinhui Li, Czajkowsky D M, Zhifeng Shao.

  The histone variant macroH2A has been found to play important regulatory roles in genomic processes, especially in regulating transcriptomes. However, whether macroH2A nucleosomes are retained on mitotic chromosomes to enable maintenance of cell-specific transcriptomes is not known. Here, examining mouse embryonic fibroblast cells (NIH-3T3) with native chromatin immunoprecipitation and sequencing (nChIP-seq), we show that the overwhelming majority (~90%) of macroH2A1 domains identified at the G1/S stage are indeed stably retained on mitotic chromosomes. Unexpectedly though, we also find that there are a number of macroH2A domains that are specific for either mitotic or G1/S cells. Notably, more than 7,000 interphase expressed genes flanked by macroH2A1 domains are loaded with macroH2A1 nucleosomes on the mitotic chromosome to form extended domains. Overall, these results reveal that, while the majority of macroH2A1 domains are indeed faithfully transmitted through the mitotic chromosomes, there is a previously unknown cell-cycle dependent exchange of macroH2A1 nucleosomes at numerous genomic loci, indicating the existence of molecular machineries for this dynamically regulated process. We anticipate that these findings will prove to be essential for the integrity of mitotic progression and the maintenance of cellular identity.

Keywords:  Histone variant macroH2A1; cell cycle; mitotic chromosomes; nChIP-seq

DOI:  https://doi.org/10.5582/bst.2023.01214
Signal Transduct Target Ther. 2023 Oct 04. 8(1): 380

Safeguarding transcriptional memory: a mitotic bookmarking role for chromatin remodelers.

Godwin Sokpor, Huu Phuc Nguyen, Tran Tuoc.

DOI: https://doi.org/10.1038/s41392-023-01610-5
Life Sci Alliance. 2023 Dec;pii: e202201720. [Epub ahead of print]6(12):

Functional plasticity in chromosome-microtubule coupling on the evolutionary time scale.

Sundar Ram Sankaranarayanan, Satya Dev Polisetty, Kuladeep Das, Arti Dumbrepatil, Bethan Medina-Pritchard, Martin Singleton, A Arockia Jeyaprakash, Kaustuv Sanyal.

The Dam1 complex is essential for mitotic progression across evolutionarily divergent fungi. Upon analyzing amino acid (aa) sequences of Dad2, a Dam1 complex subunit, we identified a conserved 10-aa-long Dad2 signature sequence (DSS). An arginine residue (R126) in the DSS is essential for viability in Saccharomyces cerevisiae that possesses point centromeres. The corresponding arginine residues are functionally important but not essential for viability in Candida albicans and Cryptococcus neoformans; both carry several kilobases long regional centromeres. The purified recombinant Dam1 complex containing either Dad2ΔDSS or Dad2R126A failed to bind microtubules (MTs) or form any visible rings like the WT complex. Intriguingly, functional analysis revealed that the requirement of the conserved arginine residue for chromosome biorientation and mitotic progression reduced with increasing centromere length. We propose that plasticity of the invariant arginine of Dad2 in organisms with regional centromeres is achieved by conditional elevation of the kinetochore protein(s) to enable multiple kinetochore MTs to bind to each chromosome. The capacity of a chromosome to bind multiple kinetochore MTs may mask the deleterious effects of such lethal mutations.

DOI: https://doi.org/10.26508/lsa.202201720
Trends Cancer. 2023 Oct 02. pii: S2405-8033(23)00173-5. [Epub ahead of print]

CIP2A coordinates phosphosignaling, mitosis, and the DNA damage response.

Srikar Nagelli, Jukka Westermarck.

  Human cancers share requirements for phosphorylation-dependent signaling, mitotic hyperactivity, and survival after DNA damage. The oncoprotein CIP2A (cancerous inhibitor of PP2A) can coordinate all these cancer cell characteristics. In addition to controlling cancer cell phosphoproteomes via inhibition of protein phosphatase PP2A, CIP2A directly interacts with the DNA damage protein TopBP1 (topoisomerase II-binding protein 1). Consequently, CIP2A allows DNA-damaged cells to enter mitosis and is essential for mitotic cells that are defective in homologous recombination (HR)-mediated DNA repair (e.g., BRCA mutants). The CIP2A-TopBP1 complex is also important for clustering fragmented chromosomes at mitosis. Clinically, CIP2A is a disease driver for basal-like triple-negative breast cancer (BL-TNBC) and a promising cancer therapy target across many cancer types.

Keywords:  G2/M arrest; PLK1; RAD51; TNBC; chromothripsis

DOI:  https://doi.org/10.1016/j.trecan.2023.09.001
EMBO Rep. 2023 Oct 05. e57227

Spindle assembly checkpoint insensitivity allows meiosis-II despite chromosomal defects in aged eggs.

Aleksandar I Mihajlović, Candice Byers, Laura Reinholdt, Greg FitzHarris.

  Chromosome segregation errors in mammalian oocyte meiosis lead to developmentally compromised aneuploid embryos and become more common with advancing maternal age. Known contributors include age-related chromosome cohesion loss and spindle assembly checkpoint (SAC) fallibility in meiosis-I. But how effective the SAC is in meiosis-II and how this might contribute to age-related aneuploidy is unknown. Here, we developed genetic and pharmacological approaches to directly address the function of the SAC in meiosis-II. We show that the SAC is insensitive in meiosis-II oocytes and that as a result misaligned chromosomes are randomly segregated. Whilst SAC ineffectiveness in meiosis-II is not age-related, it becomes most prejudicial in oocytes from older females because chromosomes that prematurely separate by age-related cohesion loss become misaligned in meiosis-II. We show that in the absence of a robust SAC in meiosis-II these age-related misaligned chromatids are missegregated and lead to aneuploidy. Our data demonstrate that the SAC fails to prevent cell division in the presence of misaligned chromosomes in oocyte meiosis-II, which explains how age-related cohesion loss can give rise to aneuploid embryos.

Keywords:  KIF18A; ageing; aneuploidy; oocyte meiosis; spindle assembly checkpoint

DOI:  https://doi.org/10.15252/embr.202357227
Int J Radiat Oncol Biol Phys. 2023 Oct 01. pii: S0360-3016(23)04983-0. [Epub ahead of print]117(2S): S140

Mitotic Errors Increase Radiation Sensitivity in Multiple Cancer Cell Types and in Laryngeal Cancer Patients.

P Cosper, M Paracha, R J Kimple, B Weaver.

PURPOSE/OBJECTIVE(S): Chromosomal instability (CIN) arises from continual mitotic errors over the course of multiple cell divisions and is common in cancer. When CIN is increased beyond a maximally tolerated threshold it leads to cell death due to loss of both copies of one or more essential chromosomes. Combining two independent insults that each cause tolerable levels of CIN results in high CIN, cell death and tumor suppression. Because radiation causes CIN, we hypothesize that pre-existing CIN sensitizes tumor cells to radiation therapy.
MATERIALS/METHODS: We characterized CIN in 4 HPV+ and 4 HPV- head and neck (HNC), 4 cervical, and 2 breast cancer cell lines before and 24 hours after 2 Gy of radiation. CIN was quantified by scoring lagging, bridge, and misaligned chromosomes, centrosome amplification, and multipolar spindles using immunofluorescence microscopy. To test our hypothesis, we created isogenic CIN and non-CIN HeLa and FaDu cells by knocking down the mitotic checkpoint protein Mad1, which induces lagging chromosomes, and by using MCF10A cells expressing tet-inducible polo-like kinase 4 (PLK4) to induce centrosome amplification. Clonogenic assays and murine tumor growth curves were used to determine radiation sensitivity in vitro and in vivo respectively. 6-chromosome FISH was used to quantify CIN and test if it was associated with local recurrence (LR) in a cohort of 29 laryngeal cancer patients treated with definitive (chemo)radiation. Significant differences were determined using a two-tailed student's t-test or Fisher's exact test.
RESULTS: A total of 2 Gy of radiation significantly increased lagging, bridge, and misaligned chromosomes and induced centrosome amplification in all cancer cell types in vitro and in vivo. Most abnormal chromosomes after radiation were acentric fragments, which are known to missegregate. Mad1 knockdown in HeLa and FaDu cells increased CIN and led to significantly increased radiation sensitivity compared to their wild-type counterparts. PLK4 overexpression in MCF10A cells led to centrosome amplification and multipolar spindles, which also increased radiation sensitivity. Additionally, mitotic errors were significantly correlated with radiation response in both HPV+ and HPV- patient derived xenograft (PDX) HNC tumors. Finally, patients with laryngeal tumors with CIN below the median of the cohort had a 31% rate of LR after therapy, while tumors with CIN greater than or equal to the median had a LR rate of only 6%.
CONCLUSION: Cancer cells with higher CIN are more sensitive to radiation therapy in vitro and in vivo. This was true for different types of mitotic errors and in different cancer models implying this is likely tumor type agnostic. Importantly, laryngeal tumors with higher baseline levels of CIN had an improved response to definitive radiation therapy, implying increased radiation sensitivity. These studies have potential implications for personalization of radiation dose.

DOI: https://doi.org/10.1016/j.ijrobp.2023.06.549
JCI Insight. 2023 Oct 05. pii: e170079. [Epub ahead of print]

Biallelic MAD2L1BP (p31comet) mutation is associated with mosaic aneuploidy and juvenile granulosa cell tumors.

Ghada M H Abdel-Salam, Susanne Hellmuth, Elise Gradhand, Stephan Käseberg, Jennifer Winter, Ann-Sophie Pabst, Maha M Eid, Holger Thiele, Peter Nürnberg, Birgit S Budde, Mohammad Reza Toliat, Ines B Brecht, Christopher Schroeder, Axel Gschwind, Stephan Ossowski, Friederike Häuser, Heidi Rossmann, Mohamed S Abdel-Hamid, Ibrahim Hegazy, Ahmed G Mohamed, Dominik T Schneider, Aida M Bertoli-Avella, Peter Bauer, Jillian N Pearring, Rolph Pfundt, Alexander Hoischen, Christian Gilissen, Dennis Strand, Ulrich Zechner, Soha A Tashkandi, Eissa A Faqeih, Olaf Stemmann, Susanne Strand, Hanno J Bolz.

  MAD2L1BP-encoded p31comet mediates Trip13-dependent disassembly of Mad2- and Rev7-containing complexes and, through this antagonism, promotes timely spindle assembly checkpoint (SAC) silencing, faithful chromosome segregation, insulin signaling and homology-directed repair (HDR) of DNA double-strand breaks. We identified a homozygous MAD2L1BP nonsense variant, R253*, in two siblings with microcephaly, epileptic encephalopathy and juvenile granulosa cell tumors of ovary and testis. Patient-derived cells exhibited high-grade mosaic variegated aneuploidy, slowed-down proliferation, and instability of truncated p31comet mRNA and protein. Corresponding recombinant p31comet was defective in Trip13-, Mad2- and Rev7-binding and unable to support SAC silencing or HDR. Furthermore, C-terminal truncation abrogated a newly identified interaction of p31comet with tp53. Another homozygous truncation, R227*, detected in an early deceased patient with low-level aneuploidy, severe epileptic encephalopathy and frequent blood glucose elevations likely corresponds to complete loss-of-function, as in Mad2l1bp-/- mice. Thus, human mutations of p31comet are linked to aneuploidy and tumor predisposition.

Keywords:  Cell cycle; Genetic diseases; Genetic instability; Genetics; Oncology

DOI:  https://doi.org/10.1172/jci.insight.170079