title: Monopolin subunit Csm1 associates with MIND complex to establish monopolar attachment of sister kinetochores at meiosis I.
abstract: Sexually reproducing organisms halve their cellular ploidy during gametogenesis by undergoing a specialized form of cell division known as meiosis. During meiosis, a single round of DNA replication is followed by two rounds of nuclear divisions (referred to as meiosis I and II). While sister kinetochores bind to microtubules emanating from opposite spindle poles during mitosis, they bind to microtubules originating from the same spindle pole during meiosis I. This phenomenon is referred to as mono-orientation and is essential for setting up the reductional mode of chromosome segregation during meiosis I. In budding yeast, mono-orientation depends on a four component protein complex referred to as monopolin which consists of two nucleolar proteins Csm1 and Lrs4, meiosis-specific protein Mam1 of unknown function and casein kinase Hrr25. Monopolin complex binds to kinetochores during meiosis I and prevents bipolar attachments. Although monopolin associates with kinetochores during meiosis I, its binding site(s) on the kinetochore is not known and its mechanism of action has not been established. By carrying out an imaging-based screen we have found that the MIND complex, a component of the central kinetochore, is required for monopolin association with kinetochores during meiosis. Furthermore, we demonstrate that interaction of monopolin subunit Csm1 with the N-terminal domain of MIND complex subunit Dsn1, is essential for both the association of monopolin with kinetochores and for monopolar attachment of sister kinetochores during meiosis I. As such this provides the first functional evidence for a monopolin-binding site at the kinetochore.
authors.affiliation: University of Warwick, Coventry, United Kingdom.
authors.forename: Sourav
authors.initials: S
authors.lastname: Sarkar
authors.forename: Rajesh T
authors.initials: RT
authors.lastname: Shenoy
authors.forename: Jacob Z
authors.initials: JZ
authors.lastname: Dalgaard
authors.forename: Louise
authors.initials: L
authors.lastname: Newnham
authors.forename: Eva
authors.initials: E
authors.lastname: Hoffmann
authors.forename: Jonathan B A
authors.initials: JB
authors.lastname: Millar
authors.forename: Prakash
authors.initials: P
authors.lastname: Arumugam
mesh_terms: D047389:Casein Kinase I / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics* / Q000378:metabolism; D004261:DNA Replication / Q000235:genetics; D018386:Kinetochores; D008540:Meiosis / Q000235:genetics*; D008870:Microtubules / Q000235:genetics; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D012854:Sister Chromatid Exchange / Q000235:genetics
chemical_list: C474335:CSM1 protein, S cerevisiae; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; C470829:Dsn1 protein, S cerevisiae; C474336:LRS4 protein, S cerevisiae; C518266:Mam1 protein, S cerevisiae; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D047389:Casein Kinase I; C070775:HRR25 protein, S cerevisiae