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Schizosaccharomyces pombe homolog of Survivin, Bir1p, exhibits a novel dynamic behavior at the spindle mid‐zone
Author(s) -
Rajagopalan Srividya,
Mishra Mithilesh,
Balasubramanian Mohan K.
Publication year - 2006
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1111/j.1365-2443.2006.00980.x
Subject(s) - biology , microbiology and biotechnology , anaphase , spindle apparatus , kinetochore , spindle pole body , chromosome segregation , aurora b kinase , schizosaccharomyces , anaphase promoting complex , spindle checkpoint , genetics , schizosaccharomyces pombe , cell cycle , cell division , chromosome , mutant , gene , cell
Members of the BIR‐domain containing Survivin family of proteins have been identified in a variety of eukaryotes and are known to play important roles in the regulation of mitosis. The Schizosaccharomyces pombe homolog of Survivin, Bir1p, is essential for chromosome condensation and spindle elongation and integrity. Bir1p, a nuclear protein, resides at the kinetochores in metaphase and anaphase A and spreads to the spindle mid‐zone in anaphase B. Here we show that this relocation requires Cdk (Cyclin dependent kinase) inactivation and intact microtubules. With the aid of a kinesin mutant, klp5 Δ, we also show that completion of anaphase A is vital for effecting Bir1p re‐location to the spindle mid‐zone. Although minimal exchange of Bir1p sub‐units occurs between the spindle and the nucleoplasm, the protein redistributes laterally within the mid‐zone region. Bir1p dynamics therefore significantly differs from that of tubulin on an anaphase B spindle, which is loaded at the plus ends of growing microtubules and shows no lateral redistribution within the spindle. Thus, Bir1p, and possibly its associated proteins, might organize a dynamic mid‐zone region that helps spindle elongation and maintenance.