Release of chromosomes from the nuclear envelope

Kanoh, Junko

doi:10.4161/nucl.23984

Cited by 10 publications

(8 citation statements)

References 23 publications

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“…Interestingly, a number of distinctly shifted bands of Rap1 were detected during meiotic prophase. Similar shifted bands of Rap1 have also been recently reported [ 18 ]. To determine if Rap1 is phosphorylated during meiosis, cell extracts were further analyzed using Phos-tag™ SDS-PAGE [ 19 ].…”

Section: Resultssupporting

confidence: 88%

Telomere protein Rap1 is a charge resistant scaffolding protein in chromosomal bouquet formation

et al. 2015

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BackgroundChromosomes reorganize in early meiotic prophase to form the so-called telomere bouquet. In fission yeast, telomeres localize to the nuclear periphery via interaction of the telomeric protein Rap1 with the membrane protein Bqt4. During meiotic prophase, the meiotic proteins Bqt1-2 bind Rap1 and tether to the spindle pole body to form the bouquet. Although it is known that this polarized chromosomal arrangement plays a crucial role in meiotic progression, the molecular mechanisms of telomere bouquet regulation are poorly understood.ResultsHere, we detected high levels of Rap1 phospho-modification throughout meiotic prophase, and identified a maximum of 35 phosphorylation sites. Concomitant phosphomimetic mutation of the modification sites suggests that Rap1 hyper-phosphorylation does not directly regulate telomere bouquet formation or dissociation. Despite the negative charge conferred by its highly phosphorylated state, Rap1 maintains interactions with its binding partners. Interestingly, mutations that change the charge of negatively charged residues within the Bqt1-2 binding site of Rap1 abolished the affinity to the Bqt1-2 complex, suggesting that the intrinsic negative charge of Rap1 is crucial for telomere bouquet formation.ConclusionsWhereas Rap1 hyper-phosphorylation observed in meiotic prophase does not have an apparent role in bouquet formation, the intrinsic negative charge of Rap1 is important for forming interactions with its binding partners. Thus, Rap1 is able to retain bouquet formation under heavily phosphorylated status.Electronic supplementary materialThe online version of this article (doi:10.1186/s12915-015-0149-x) contains supplementary material, which is available to authorized users.

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Section: Resultssupporting

confidence: 88%

Telomere protein Rap1 is a charge resistant scaffolding protein in chromosomal bouquet formation

et al. 2015

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“…pombe undergo closed mitosis, whereas the majority of higher eukaryotes perform open mitosis, during which the nuclear envelope is disassembled. The release of the nuclear content enables spindle microtubules to access kinetochores (Kanoh 2013 ). Nuclear envelope breakdown does not occur during closed mitosis.…”

Section: Division Abnormalitiesmentioning

confidence: 99%

Genetic instability in budding and fission yeast—sources and mechanisms

Skoneczna

Kaniak

Skoneczny

2015

FEMS Microbiology Reviews

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Cells are constantly confronted with endogenous and exogenous factors that affect their genomes. Eons of evolution have allowed the cellular mechanisms responsible for preserving the genome to adjust for achieving contradictory objectives: to maintain the genome unchanged and to acquire mutations that allow adaptation to environmental changes. One evolutionary mechanism that has been refined for survival is genetic variation. In this review, we describe the mechanisms responsible for two biological processes: genome maintenance and mutation tolerance involved in generations of genetic variations in mitotic cells of both Saccharomyces cerevisiae and Schizosaccharomyces pombe. These processes encompass mechanisms that ensure the fidelity of replication, DNA lesion sensing and DNA damage response pathways, as well as mechanisms that ensure precision in chromosome segregation during cell division. We discuss various factors that may influence genome stability, such as cellular ploidy, the phase of the cell cycle, transcriptional activity of a particular region of DNA, the proficiency of DNA quality control systems, the metabolic stage of the cell and its respiratory potential, and finally potential exposure to endogenous or environmental stress.

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“…Rap1 is heavily phosphorylated during both mitosis and meiosis (15,16,32). Several phosphorylation sites are within or in the vicinity of the Bqt4-binding motif, including S497, S509, S510, S512 and S513 (15,32).…”

Section: Resultsmentioning

confidence: 99%

“…Telomeres are the best-characterized chromosomal sites that are dynamically associated with the NE (10,14). In S. pombe , telomeres are tethered to the NE during interphase, and are transiently dissociated from the NE during mitosis (15,16). The dissociation of telomeres from the NE is essential for accurate chromosome segregation (15).…”

Section: Introductionmentioning

confidence: 99%

“…The dissociation of telomeres from the NE is essential for accurate chromosome segregation (15). This dissociation relies on the mitosis-specific phosphorylation of Rap1-S513 by Cdc2 to disrupt Bqt4–Rap1 interaction (15,16). In meiotic prophase, the NE-tethered telomeres are clustered to the spindle pole body (SPB) to form a bouquet-like configuration (14,17).…”

Section: Introductionmentioning

confidence: 99%

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Structural insights into chromosome attachment to the nuclear envelope by an inner nuclear membrane protein Bqt4 in fission yeast

Sun

Takeshita

et al. 2018

Nucleic Acids Research

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The dynamic association of chromosomes with the nuclear envelope (NE) is essential for chromosome maintenance. Schizosaccharomyces pombe inner nuclear membrane protein Bqt4 plays a critical role in connecting telomeres to the NE, mainly through a direct interaction with the telomeric protein Rap1. Bqt4 also interacts with Lem2 for pericentric heterochromatin maintenance. How Bqt4 coordinates the interactions with different proteins to exert their functions is unclear. Here, we report the crystal structures of the N-terminal domain of Bqt4 in complexes with Bqt4-binding motifs from Rap1, Lem2, and Sad1. The structural, biochemical and cellular analyses reveal that the N-terminal domain of Bqt4 is a protein-interaction module that recognizes a consensus motif and plays essential roles in telomere-NE association and meiosis progression. Phosphorylation of Bqt4-interacting proteins may act as a switch to regulate these interactions during cell cycles. Our studies provide structural insights into the identification and regulation of Bqt4-mediated interactions.

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Release of chromosomes from the nuclear envelope

Cited by 10 publications

References 23 publications

Telomere protein Rap1 is a charge resistant scaffolding protein in chromosomal bouquet formation

Telomere protein Rap1 is a charge resistant scaffolding protein in chromosomal bouquet formation

Genetic instability in budding and fission yeast—sources and mechanisms

Structural insights into chromosome attachment to the nuclear envelope by an inner nuclear membrane protein Bqt4 in fission yeast

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