Suppressors of Bir1p (Survivin) identify roles for the chromosomal passenger protein Pic1p (INCENP) and the replication initiation factor Psf2p in chromosome segregation.
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.
Huang
Han-Kuei
HK
Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
Bailis
Julie M
JM
Leverson
Joel D
JD
Gómez
Eliana B
EB
Forsburg
Susan L
SL
Hunter
Tony
T
D000071450:ATP Binding Cassette Transporter, Subfamily B, Member 3; D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D020090:Chromosome Segregation / Q000235:genetics / Q000502:physiology*; D048749:Cytokinesis; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005800:Genes, Fungal; D006367:HeLa Cells; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*; D000077022:Survivin
D000071450:ATP Binding Cassette Transporter, Subfamily B, Member 3; D018528:ATP-Binding Cassette Transporters; C107489:BIRC5 protein, human; D002868:Chromosomal Proteins, Non-Histone; D005656:Fungal Proteins; C083767:INCENP protein, human; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D029702:Schizosaccharomyces pombe Proteins; D000077022:Survivin; C071692:TAP2 protein, human