Abstract
Cohesion between sister chromatids by the cohesin protein complex ensures accurate chromosome segregation and enables recombinational DNA repair. Sister chromatid cohesion is promoted by acetylation of the SMC3 subunit of cohesin by the ESCO2 acetyltransferase, inhibiting cohesin release from chromatin. The interaction of ESCO2 with the DNA replication machinery, in part through PCNA-interacting protein (PIP) motifs in ESCO2, is required for full cohesion establishment. Recent reports have suggested that Cul4-dependent degradation regulates the level of ESCO2 protein during late S/G2 phase of the cell cycle. To follow up on these observations, we have characterized ESCO2 stability in Xenopus egg extracts, a cell-free system that recapitulates cohesion establishment in vitro. We found that ESCO2 was stable during DNA replication in this system. Indeed, further challenging the system by inducing DNA damage signaling or increasing the number of nuclei undergoing DNA replication had no significant impact on the stability of ESCO2. In transgenic somatic cell lines, we did not see evidence of GFP-ESCO2 degradation during S phase of the cell cycle using either flow cytometry or live-cell imaging techniques. We conclude that ESCO2 is stable during DNA replication in both embryonic and somatic cells.
Competing Interest Statement
The authors have declared no competing interest.
Abbreviations
- APC
- (Anaphase promoting complex)
- Cdh1
- (Cdc20 homolog 1)
- Cdt1
- (Chromatin licensing and DNA replication factor 1)
- Chk1
- (Checkpoint kinase 1)
- CRL4
- (Cullin-RING ubiquitin ligase complex 4)
- CSF
- (Cytostatic factor)
- Cul4
- (Cullin-4)
- DCAF1
- (DDB1-Cul4-associating factor 1)
- DDB1
- (DNA damage-binding protein 1)
- Dox
- (doxycycline)
- Eco1
- (Establishment of cohesion 1)
- ESCO2
- (Establishment of Cohesion 1 homolog 2)
- FoxM1
- (Forkhead box M1)
- MCM
- (Minichromosome maintenance)
- PCNA
- (Proliferating cell nuclear antigen)
- PIP
- (PCNA-interacting protein)
- SAMHD1
- (SAM and HD domain containing deoxynucleoside triphosphate triphosphohydrolase 1)
- SMC3
- (Structural Maintenance of Chromosomes 3)
- VprBP
- (Viral protein R binding protein)
- WAPL
- (Wings apart-like protein homolog)