Cohesin rings devoid of Scc3 and Pds5 maintain their stable association with the DNA.
Cohesin is a protein complex that forms a ring around sister chromatids thus holding them together. The ring is composed of three proteins: Smc1, Smc3 and Scc1. The roles of three additional proteins that associate with the ring, Scc3, Pds5 and Wpl1, are not well understood. It has been proposed that these three factors form a complex that stabilizes the ring and prevents it from opening. This activity promotes sister chromatid cohesion but at the same time poses an obstacle for the initial entrapment of sister DNAs. This hindrance to cohesion establishment is overcome during DNA replication via acetylation of the Smc3 subunit by the Eco1 acetyltransferase. However, the full mechanistic consequences of Smc3 acetylation remain unknown. In the current work, we test the requirement of Scc3 and Pds5 for the stable association of cohesin with DNA. We investigated the consequences of Scc3 and Pds5 depletion in vivo using degron tagging in budding yeast. The previously described DHFR-based N-terminal degron as well as a novel Eco1-derived C-terminal degron were employed in our study. Scc3 and Pds5 associate with cohesin complexes independently of each other and require the Scc1 "core" subunit for their association with chromosomes. Contrary to previous data for Scc1 downregulation, depletion of either Scc3 or Pds5 had a strong effect on sister chromatid cohesion but not on cohesin binding to DNA. Quantity, stability and genome-wide distribution of cohesin complexes remained mostly unchanged after the depletion of Scc3 and Pds5. Our findings are inconsistent with a previously proposed model that Scc3 and Pds5 are cohesin maintenance factors required for cohesin ring stability or for maintaining its association with DNA. We propose that Scc3 and Pds5 specifically function during cohesion establishment in S phase.
Friedrich Miescher Laboratory of the Max Planck Society, Tübingen, Germany.
Irina
I
Kulemzina
Martin R
MR
Schumacher
Vikash
V
Verma
Jochen
J
Reiter
Janina
J
Metzler
Antonio Virgilio
AV
Failla
Christa
C
Lanz
Vipin T
VT
Sreedharan
Gunnar
G
Rätsch
Dmitri
D
Ivanov
D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D002842:Chromatids / Q000235:genetics / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics* / Q000378:metabolism; D020090:Chromosome Segregation / Q000235:genetics; D015825:Chromosomes, Fungal; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D016196:S Phase / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D000097722:Cohesins; D000098550:Structural Maintenance of Chromosome Protein 1
D000123:Acetyltransferases; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004271:DNA, Fungal; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D000097722:Cohesins; D000098550:Structural Maintenance of Chromosome Protein 1; C119635:IRR1 protein, S cerevisiae; C490529:MCD1 protein, S cerevisiae; C427726:PDS5 protein, S cerevisiae; C120372:SMC3 protein, S cerevisiae; C118076:ECO1 protein, S cerevisiae