Timeless functions independently of the Tim-Tipin complex to promote sister chromatid cohesion in normal human fibroblasts

Smith‐Roe, Stephanie L.; Patel, Shivani; Simpson, Dennis A.; Zhou, Ying; Rao, Shangbang; Ibrahim, Joseph G.; Kaiser‐Rogers, Kathleen; Cordeiro‐Stone, Marila

doi:10.4161/cc.10.10.15613

Cited by 29 publications

(30 citation statements)

References 43 publications

(85 reference statements)

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“…scaling of sister chromatid discohesion was generated from smith-Roe et al (2011). 14 The effect of co-targeting TIMeLess and aTR on sCC was not reported in smith-Roe et al (2011), but is reported here as 4.7 ± 2.5% for NhF1-hTeRT (scaled into Fig. 8) and 30.5 ± 12.6% for NhF10-hTeRT.…”

Section: Discussionmentioning

confidence: 76%

“…The clade containing the results for control, ATR, CLASPIN, CHK1 and TIPIN siRNAs was divided into subsets, showing distinct separation of ATR-or CHK1-depletion phenotypes. TIMELESS depletions were separated from the other depletions due to the specific contribution of TIMELESS to sister chromatid cohesion in NHF lines (SCC data obtained from Smith-Roe et al 2011 14 ). Overall, these results indicate that ATR, CHK1 and TIMELESS support different functions to preserve intrinsic genomic stability, some of which must be independent of ATR-CHK1 signaling.…”

Section: Discussionmentioning

confidence: 83%

“…S1E), as TIMELESS is required for sister chromatid cohesion (SCC) in human cells. 14,26 Chromosome exchanges are generated from erroneous rejoining of broken chromosomes. Exchanges were not detected in > 1,400 metaphases from NHF1-hTERT and NHF10-hTERT electroporated with NTC siRNA.…”

Section: Resultsmentioning

confidence: 99%

“…The higher level of chromosomal aberrations produced when targeting TIMELESS compared with targeting TIPIN, CHK1 or CLASPIN may have been related to the dramatic sister chromatid cohesion defect observed in TIMELESS-depleted fibroblasts 14 (and represented in Fig. 8).…”

Section: Discussionmentioning

confidence: 99%

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Separation of intra-S checkpoint protein contributions to DNA replication fork protection and genomic stability in normal human fibroblasts

Smith‐Roe¹,

Patel

Zhou

et al. 2013

Cell Cycle

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Section: Discussionmentioning

confidence: 76%

Section: Discussionmentioning

confidence: 83%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Separation of intra-S checkpoint protein contributions to DNA replication fork protection and genomic stability in normal human fibroblasts

Smith‐Roe¹,

Patel

Zhou

et al. 2013

Cell Cycle

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“…In undamaged cells, TIM dysfunction decreases the rate of replication fork progression and uncouples the DNA polymerase and MCM2-7 helicase activity (21). TIM-TIPIN also facilitates the loading of cohesin subunits to establish sister chromatid cohesions (23,24). The role of…”

mentioning

confidence: 99%

TIMELESS Suppresses the Accumulation of Aberrant CDC45·MCM2-7·GINS Replicative Helicase Complexes on Human Chromatin

Wang

et al. 2016

Journal of Biological Chemistry

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The replication licensing factor CDC6 recruits the MCM2-7 replicative helicase to the replication origin, where MCM2-7 is activated to initiate DNA replication. MCM2-7 is activated by both the CDC7-Dbf4 kinase and cyclin-dependent kinase and via interactions with CDC45 and go-ichi-ni-san complex (GINS) to form the CDC45⅐MCM2-7⅐GINS (CMG) helicase complex. TIMELESS (TIM) is important for the subsequent coupling of CMG activity to DNA polymerases for efficient DNA synthesis. However, the mechanism by which TIM regulates CMG activity for proper replication fork progression remains unclear. Here we show that TIM interacts with MCM2-7 prior to the initiation of DNA replication. TIM depletion in various human cell lines results in the accumulation of aberrant CMG helicase complexes on chromatin. Importantly, the presence of these abnormal CMG helicase complexes is not restricted to cells undergoing DNA synthesis. Furthermore, even though these aberrant CMG complexes interact with the DNA polymerases on human chromatin, these complexes are not phosphorylated properly by cyclin-dependent kinase/CDC7-Dbf4 kinase and exhibit reduced DNA unwinding activity. This phenomenon coincides with a significant accumulation of the p27 and p21 replication inhibitors, reduced chromatin association of CDC6 and cyclin E, and a delay in S phase entry. Our results provide the first evidence that TIM is required for the correct chromatin association of the CMG complex to allow efficient DNA replication.During cell growth, faithful DNA duplication is essential for correctly transmitting genetic material to daughter cells during cell division, and defects in this process can result in genome instability, tumorigenesis, or cell death. During DNA replication, double-stranded DNA must be unwound by the MCM2-7 a hexameric helicase to generate ssDNA, 2 which is then used as the template for DNA synthesis by DNA polymerase. However, even though there is an abundance of MCM2-7 protein on the chromatin throughout the cell cycle, most of the MCM2-7 is kept inactive, and only a small population is recruited and associated with active replicons to participate in DNA synthesis (1-3). During early G 1 phase, the MCM2-7 protein is recruited to the active replication origins, where it forms part of the pre-replication complex, and its recruitment requires the CDC6 and CDT1 licensing factors (4, 5). To ensure the accurate timing of replication initiation, the activity of the chromatin-bound MCM2-7 protein is tightly regulated both by post-translational modifications and protein-protein interactions. Specifically, the catalytic activity of the MCM2-7 helicase is suppressed during G 1 phase and can only be activated both via the interaction with GINS and CDC45, which forms the CMG complex, and via phosphorylation by DDK and CDK during replication initiation (6, 7). Mammalian TIM is an essential protein for embryonic development (8). TIM and its interacting protein, TIPIN, are highly conserved replication factors that directly interact with the MCM2-7 helicase...

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Linking Chromosome Duplication and Segregation via Sister Chromatid Cohesion

Leman

Noguchi

2014

Methods in Molecular Biology

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DNA replication during S phase generates two identical copies of each chromosome. Each chromosome is destined for a daughter cell, but each daughter must receive one and only one copy of each chromosome. To ensure accurate chromosome segregation, eukaryotic cells are equipped with a mechanism to pair the chromosomes during chromosome duplication and hold the pairs until a bi-oriented mitotic spindle is formed and the pairs are pulled apart. This mechanism is known as sister chromatid cohesion, and its actions span the entire cell cycle. During G1, before DNA is copied during S phase, proteins termed cohesins are loaded onto DNA. Paired chromosomes are held together through G2 phase, and finally the cohesins are dismantled during mitosis. The processes governing sister chromatid cohesion ensure that newly replicated sisters are held together from the moment they are generated to the metaphase–anaphase transition, when sisters separate.

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Timeless functions independently of the Tim-Tipin complex to promote sister chromatid cohesion in normal human fibroblasts

Cited by 29 publications

References 43 publications

Separation of intra-S checkpoint protein contributions to DNA replication fork protection and genomic stability in normal human fibroblasts

Separation of intra-S checkpoint protein contributions to DNA replication fork protection and genomic stability in normal human fibroblasts

TIMELESS Suppresses the Accumulation of Aberrant CDC45·MCM2-7·GINS Replicative Helicase Complexes on Human Chromatin

Linking Chromosome Duplication and Segregation via Sister Chromatid Cohesion

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