Dataset Information

Suppressors of Bir1p (Survivin) identify roles for the chromosomal passenger protein Pic1p (INCENP) and the replication initiation factor Psf2p in chromosome segregation.

ABSTRACT: Fission yeast Bir1p/Cut17p/Pbh1p, the homolog of human Survivin, is a conserved chromosomal passenger protein that is required for cell division and cytokinesis. To study how Bir1p promotes accurate segregation of chromosomes, we generated and analyzed a temperature-sensitive allele, bir1-46, and carried out genetic screens to find genes that interact with bir1(+). We identified Psf2p, a component of the GINS complex required for DNA replication initiation, as a high-copy-number suppressor of the bir1-46 growth defect. Loss of Psf2p function by depletion or deletion or by use of a temperature-sensitive allele, psf2-209, resulted in chromosome missegregation that was associated with mislocalization of Bir1p. We also found that the human homolog of Psf2p, PSF2, was required for proper chromosome segregation. In addition, we observed that high-copy-number expression of Pic1p, the fission yeast homolog of INCENP (inner centromere protein), suppressed bir1-46. Pic1p exhibited a localization pattern typical of chromosomal passenger proteins. Deletion of pic1(+) caused chromosome missegregation phenotypes similar to those of bir1-46. Our data suggest that Bir1p and Pic1p act as part of a conserved chromosomal passenger complex and that Psf2p/GINS indirectly affects the localization and function of this complex in chromosome segregation, perhaps through an S-phase role in centromere replication.

SUBMITTER: Huang HK

PROVIDER: S-EPMC1265766 | biostudies-literature | 2005 Oct

REPOSITORIES: biostudies-literature

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Suppressors of Bir1p (Survivin) identify roles for the chromosomal passenger protein Pic1p (INCENP) and the replication initiation factor Psf2p in chromosome segregation.

Huang Han-Kuei HK Bailis Julie M JM Leverson Joel D JD Gómez Eliana B EB Forsburg Susan L SL Hunter Tony T

Molecular and cellular biology 20051001 20

Fission yeast Bir1p/Cut17p/Pbh1p, the homolog of human Survivin, is a conserved chromosomal passenger protein that is required for cell division and cytokinesis. To study how Bir1p promotes accurate segregation of chromosomes, we generated and analyzed a temperature-sensitive allele, bir1-46, and carried out genetic screens to find genes that interact with bir1(+). We identified Psf2p, a component of the GINS complex required for DNA replication initiation, as a high-copy-number suppressor of th ...[more]

PMID: 16199877

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Project description:A single inner centromere protein (INCENP) found throughout eukaryotes modulates Aurora B kinase activity and chromosomal passenger complex (CPC) localization, which is essential for timely mitotic progression. It has been proposed that INCENP might act as a rheostat to regulate Aurora B activity through mitosis, with successively higher activity threshold levels for chromosome alignment, the spindle checkpoint, anaphase spindle transfer and finally spindle elongation and cytokinesis. It remains mechanistically unclear how this would be achieved. Here, we reveal that the urochordate, Oikopleura dioica, possesses two INCENP paralogs, which display distinct localizations and subfunctionalization in order to complete M-phase. INCENPa was localized on chromosome arms and centromeres by prometaphase, and modulated Aurora B activity to mediate H3S10/S28 phosphorylation, chromosome condensation, spindle assembly and transfer of the CPC to the central spindle. Polo-like kinase (Plk1) recruitment to CDK1 phosphorylated INCENPa was crucial for INCENPa-Aurora B enrichment on centromeres. The second paralog, INCENPb was enriched on centromeres from prometaphase, and relocated to the central spindle at anaphase onset. In the absence of INCENPa, meiotic spindles failed to form, and homologous chromosomes did not segregate. INCENPb was not required for early to mid M-phase events but became essential for the activity and localization of Aurora B on the central spindle and midbody during cytokinesis in order to allow abscission to occur. Together, our results demonstrate that INCENP paralog switching on centromeres modulates Aurora B kinase localization, thus chronologically regulating CPC functions during fast embryonic divisions in the urochordate O. dioica. Abbreviations: CCAN: constitutive centromere-associated network; CENPs: centromere proteins; cmRNA: capped messenger RNA; CPC: chromosomal passenger complex; INCENP: inner centromere protein; Plk1: polo-like kinase 1; PP1: protein phosphatase 1; PP2A: protein phosphatase 2A; SAC: spindle assembly checkpoint; SAH: single α-helix domain.

Dataset Information

Suppressors of Bir1p (Survivin) identify roles for the chromosomal passenger protein Pic1p (INCENP) and the replication initiation factor Psf2p in chromosome segregation.

Publications

Suppressors of Bir1p (Survivin) identify roles for the chromosomal passenger protein Pic1p (INCENP) and the replication initiation factor Psf2p in chromosome segregation.

Similar Datasets

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