Reconstruction of the Kinetochore during Meiosis in Fission Yeast Schizosaccharomyces pombe

Abstract

During the transition from mitosis to meiosis, the kinetochore undergoes significant reorganization, switching from a bipolar to a monopolar orientation. To examine the centromere proteins that are involved in fundamental reorganization in meiosis, we observed the localization of 22 mitotic and 2 meiotic protein components of the kinetochore during meiosis in living cells of the fission yeast. We found that the 22 mitotic proteins can be classified into three groups: the Mis6-like group, the NMS (Ndc80-Mis12-Spc7) group, and the DASH group, based on their meiotic behavior. Mis6-like group proteins remain at the centromere throughout meiosis. NMS group proteins disappear from the centromere at the onset of meiosis and reappear at the centromere in two steps in late prophase. DASH group proteins appear shortly before metaphase of meiosis I. These observations suggest that Mis6-like group proteins constitute the structural basis of the centromere and that the NMS and DASH group proteins reassemble to establish the functional metaphase kinetochore. On the other hand, the meiosis-specific protein Moa1, which plays an important role in forming the meiotic monopolar kinetochore, is loaded onto the centromere significantly earlier than the NMS group, whereas another meiosis-specific protein, Sgo1, is loaded at times similar to the NMS group.

Histone Variant H2A.Z Regulates Centromere Silencing and Chromosome Segregation in Fission Yeast

“…Among them, only Cnp3 has been implicated in centromere function (51). Cnp3 is a centromere protein homologous to mammalian CENP-C and is required for chromosome segregation (52)(53)(54). Our ChIP-chip results showed that H2A.Z Pht1 is enriched at the promoter region of CENP-C Cnp3 , which was confirmed by PCR-based quantification (Fig.…”

The telomere bouquet regulates meiotic centromere assembly

“…The outer kinetochore complex was visualized by live analysis of meiotic cells harbouring an endogenously tagged functional allele of Dad1, a component of the DASH complex, which interacts directly with microtubules. In a wt background, Dad1 remains associated with the centromere throughout meiosis [28][29][30] (Supplementary Fig. 2).…”

“…To examine localization of additional factors at the base of the kinetochore, we assessed the cenI-TetO/R localization of endogenously tagged and functional Mis6, an essential Cnp1-loading factor 24 that remains on the centromere throughout meiosis in a wt setting 28 . The cenI-TetO/R signal remains unsegregated in 12.3% of bqt1∆ meiocytes, in line with the representation of one of the three fission yeast centromeres by cenI-TetO/R, and cenI-TetO/R fails to associate with visible Mis6-GFP in 88% of those cases ( Supplementary Fig.…”

Reconstruction of the kinetochore: a prelude to meiosis

“…Recent studies have revealed that a group of proteins disappear from the centromere during meiotic prophase, regulated by mating pheromone signaling [22,23]. In mitotic interphase, a number of proteins assemble at the centromere and connect the centromere to the SPB; when the cell enters mitosis, they form the kinetochore as an interface between the centromere and spindle microtubules.…”