Cohesion Between Sister Chromatids Must Be Established During DNA Replication

Curr Biol. 1998 Oct 8;8(20):1095-101. doi: 10.1016/s0960-9822(98)70463-4.

Abstract

Background: Cohesion between sister chromatids, which opposes the splitting force exerted by the mitotic spindle during metaphase, is essential for their segregation to opposite poles of the cell during anaphase. In Saccharomyces cerevisiae, cohesion depends on a set of chromosomal proteins called cohesins, which include structural maintenance of chromosomes 1p (Smc1p), Smc3p and sister chromatid cohesion 1p (Scc1p). Strains with mutations in the genes encoding these proteins separate sister chromatids prematurely and fail to align them in metaphase. This leads to missegregation of chromosomes in the following anaphase.

Results: In a normal cell cycle, Scc1p was synthesized and recruited to chromosomes at the onset of S phase. Using cells that expressed Scc1p exclusively from a galactose-inducible promoter, we showed that if Scc1p was synthesised only after completion of S phase, it still bound to chromosomes but failed to promote sister chromatid cohesion.

Conclusions: Cohesion between sister chromatids must be established during DNA replication, possibly following the passage of a replication fork. Furthermore, Scc1p (and other cohesins) are needed both for maintaining cohesion during mitosis and for establishing it during S phase. Establishment of sister chromatid cohesion is therefore an essential but hitherto neglected aspect of S phase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Chromatids*
  • Chromosomal Proteins, Non-Histone
  • Chromosomes, Fungal / metabolism
  • DNA Replication*
  • G2 Phase
  • Nuclear Proteins
  • Phosphoproteins
  • S Phase
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins

Substances

  • Cell Cycle Proteins
  • Chromosomal Proteins, Non-Histone
  • MCD1 protein, S cerevisiae
  • Nuclear Proteins
  • Phosphoproteins
  • Saccharomyces cerevisiae Proteins