title: The essentiality of the fungus-specific Dam1 complex is correlated with a one-kinetochore-one-microtubule interaction present throughout the cell cycle, independent of the nature of a centromere.
abstract: A fungus-specific outer kinetochore complex, the Dam1 complex, is essential in Saccharomyces cerevisiae, nonessential in fission yeast, and absent from metazoans. The reason for the reductive evolution of the functionality of this complex remains unknown. Both Candida albicans and Schizosaccharomyces pombe have regional centromeres as opposed to the short-point centromeres of S. cerevisiae. The interaction of one microtubule per kinetochore is established both in S. cerevisiae and C. albicans early during the cell cycle, which is in contrast to the multiple microtubules that bind to a kinetochore only during mitosis in S. pombe. Moreover, the Dam1 complex is associated with the kinetochore throughout the cell cycle in S. cerevisiae and C. albicans but only during mitosis in S. pombe. Here, we show that the Dam1 complex is essential for viability and indispensable for proper mitotic chromosome segregation in C. albicans. The kinetochore localization of the Dam1 complex is independent of the kinetochore-microtubule interaction, but the function of this complex is monitored by a spindle assembly checkpoint. Strikingly, the Dam1 complex is required to prevent precocious spindle elongation in premitotic phases. Thus, constitutive kinetochore localization associated with a one-microtubule-one kinetochore type of interaction, but not the length of a centromere, is correlated with the essentiality of the Dam1 complex.
authors.affiliation: Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India.
authors.forename: Jitendra
authors.initials: J
authors.lastname: Thakur
authors.forename: Kaustuv
authors.initials: K
authors.lastname: Sanyal
mesh_terms: D002176:Candida albicans / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle; D002503:Centromere / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D018386:Kinetochores / Q000378:metabolism*; D059566:M Phase Cell Cycle Checkpoints; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport; D013045:Species Specificity
chemical_list: D005656:Fungal Proteins; D008869:Microtubule-Associated Proteins