The mammalian Cut homeodomain protein functions as a cell-cycle-dependent transcriptional repressor which downmodulates p21WAF1/CIP1/SDI1 in S phase

Mitogenic stimulation of quiescent cells not only triggers the cell division cycle but also induces an increase in cell volume, associated with an activation of cellular metabolism. It is therefore likely that genes encoding enzymes and other proteins involved in energy metabolism and biosynthetic pathways represent a major class of mitogen-induced genes. In the present study, we investigated in the non-established human fibroblast line WI-38 the induction by mitogens of 17 genes whose products play a role in different metabolic processes. We show that these genes fall into 4 different categories, i.e. non-induced genes, immediate early (IE) primary genes, delayed early (DE) secondary genes and late genes reaching peak levels in S-phase. In addition, we have analysed the regulation of these genes during normal cell cycle progression, using HL-60 cells separated by counterflow elutriation. A clear cell cycle regulation was seen with those genes that are induced in S-phase, i.e. thymidine kinase, thymidylate synthase and dihydrofolate reductase. In addition, two DE genes showed a cell cycle dependent expression. Ornithine decarboxylase mRNA increased around mid-G1, reaching maximum levels in S/G2, while hexokinase mRNA expression was highest in early G1. In contrast, the expression of other DE and IE genes did not fluctuate during the cell cycle, a result that was confirmed with elutriated WI-38 and serum-stimulated HL-60 cells. These observations suggest that G0-->S and G1-->S transition are distinct processes, exhibiting characteristic programmes of gene regulation, and merging around S-phase entry.

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A Role for NIPA in DNA Damage Response.

Blood ◽

10.1182/blood.v104.11.1265.1265 ◽

2004 ◽

Vol 104 (11) ◽

pp. 1265-1265

Author(s):

Christine von Klitzing ◽

Florian Bassermann ◽

Stephan W. Morris ◽

Christian Peschel ◽

Justus Duyster

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Dna Damage Response ◽

Phosphorylation Site ◽

Genotoxic Stress ◽

S Phase ◽

Damage Response ◽

A Cell ◽

Cycle Dependent

Abstract The nuclear interaction partner of ALK (NIPA) is a nuclear protein identified by our group in a screen for NPM-ALK interaction partners. We recently reported that NIPA is an F-box protein that assembles with SKP1, Cul1 and Roc1 to establish a novel SCF-type E3 ubiquitin ligase. The formation of the SCFNIPA complex is regulated by cell cycle-dependent phosphorylation of NIPA that restricts SCFNIPA assembly from G1- to late S-phase, thus allowing its substrates to be active from late S-phase throughout mitosis. Proteins involved in cell cycle regulation frequently play a role in DNA damage checkpoints. We therefore sought to determine whether NIPA has a function in the cellular response to genotoxic stress. For this reason we treated NIH/3T3 cells with various DNA-damaging agents. Surprisingly, we observed phosphorylation of NIPA in response to some of these agents, including UV radiation. This phosphorylation was cell cycle phase independent and thus independent of the physiological cell cycle dependent phosphorylation of NIPA. The relevant phosphorylation site is identical to the respective site in the course of cell cycle-dependent phosphorylation of NIPA. Thus, phosphorylation of NIPA upon genotoxic stress would inactivate the SCFNIPA complex in a cell cycle independent manner. Interestingly, this phosphorylation site lies within a consensus site of the Chk1/Chk2 checkpoint kinases. These kinases are central to DNA damage checkpoint signaling. Chk1 is activated by ATR in response to blocked replication forks as they occur after treatment with UV. We performed experiments using the ATM/ATR inhibitor caffeine and the Chk1 inhibitor SB218078 to investigate a potential role of Chk1 in NIPA phosphorylation. Indeed, we found both inhibitors to prevent UV-induced phosphorylation of NIPA. Current experiments applying Chk1 knock-out cells will unravel the role of Chk1 in NIPA phosphorylation. Additional experiments were performed to investigate a function for NIPA in DNA-damage induced apoptosis. In this regard, we observed overexpression of NIPA WT to induce apoptosis in response to UV, whereas no proapoptotic effect was seen with the phosphorylation deficient NIPA mutant. Therefore, the phosphorylated form of NIPA may be involved in apoptotic signaling pathways. In summary, we present data suggesting a cell cycle independent function for NIPA. This activity is involved in DNA damage response and may be involved in regulating apoptosis upon genotoxic stress.

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EGT2 gene transcription is induced predominantly by Swi5 in early G1.

Molecular and Cellular Biology ◽

10.1128/mcb.16.7.3264 ◽

1996 ◽

Vol 16 (7) ◽

pp. 3264-3274 ◽

Cited By ~ 61

Author(s):

B Kovacech ◽

K Nasmyth ◽

T Schuster

Keyword(s):

Cell Cycle ◽

Transcriptional Activation ◽

Cell Separation ◽

S Phase ◽

Dependent Manner ◽

Yeast Saccharomyces Cerevisiae ◽

Concentration Dependent Manner ◽

A Cell ◽

Cycle Dependent ◽

Ho Gene

In a screen for cell cycle-regulated genes in the yeast Saccharomyces cerevisiae, we have identified a gene, EGT2, which is involved in cell separation in the G1 stage of the cell cycle. Transcription of EGT2 is tightly regulated in a cell cycle-dependent manner. Transcriptional levels peak at the boundary of mitosis and early G1 The transcription factors responsible for EGT2 expression in early G1 are Swi5 and, to a lesser extent, Ace2. Swi5 is involved in the transcriptional activation of the HO gene during late G1 and early S phase, and Ace2 induces CTS1 transcription during early and late G1 We show that Swi5 activates EGT2 transcription as soon as it enters the nucleus at the end of mitosis in a concentration-dependent manner. Since Swi5 is unstable in the nucleus, its level drops rapidly, causing termination of EGT2 transcription before cells are committed to the next cell cycle. However, Swi5 is still able to activate transcription of HO in late G1 in conjunction with additional activators such as Swi4 and Swi6.

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Regulation of Geminin Functions by Cell Cycle-Dependent Nuclear-Cytoplasmic Shuttling

Molecular and Cellular Biology ◽

10.1128/mcb.00123-07 ◽

2007 ◽

Vol 27 (13) ◽

pp. 4737-4744 ◽

Cited By ~ 13

Author(s):

Lingfei Luo ◽

Yvonne Uerlings ◽

Nicole Happel ◽

Naisana S. Asli ◽

Hendrik Knoetgen ◽

...

Keyword(s):

Cell Cycle ◽

Protein Degradation ◽

Gene Transcription ◽

S Phase ◽

Minichromosome Maintenance ◽

Protein Functions ◽

Mcm Complex ◽

Cycle Dependent ◽

Dna Rereplication

ABSTRACT The geminin protein functions both as a DNA rereplication inhibitor through association with Cdt1 and as a repressor of Hox gene transcription through the polycomb pathway. Here, we report that the functions of avian geminin are coordinated with and regulated by cell cycle-dependent nuclear-cytoplasmic shuttling. In S phase, geminin enters nuclei and inhibits both loading of the minichromosome maintenance (MCM) complex onto chromatin and Hox gene transcription. At the end of mitosis, geminin is exported from nuclei by the exportin protein Crm1 and is unavailable in the nucleus during the next G1 phase, thus ensuring proper chromatin loading of the MCM complex and Hox gene transcription. This mechanism for regulating the functions of geminin adds to distinct mechanisms, such as protein degradation and ubiquitination, applied in other vertebrates.

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Dynamic cell cycle-dependent phosphorylation modulates CENP-L-CENP-N centromere recruitment

10.1101/2021.12.17.473210 ◽

2021 ◽

Author(s):

Alexandra P Navarro ◽

Iain M Cheeseman

Keyword(s):

Cell Cycle ◽

Chromosome Segregation ◽

S Phase ◽

Dependent Manner ◽

Dynamic Cell ◽

A Cell ◽

Cycle Dependent ◽

Unique Cell ◽

Localization Behavior ◽

Constitutive Phosphorylation

The kinetochore is a macromolecular structure that is required to ensure proper chromosome segregation during each cell division. The kinetochore is assembled upon a platform of the 16-subunit Constitutive Centromere Associated Network (CCAN), which is present at centromeres throughout the cell cycle. The nature and regulation of CCAN assembly, interactions, and dynamics required to facilitate changing centromere properties and requirements remain to be fully elucidated. The CENP-LN CCAN sub-complex displays a unique cell cycle-dependent localization behavior, peaking in S phase. Here, we demonstrate that phosphorylation of CENP-L and CENP-N controls CENP-LN complex formation and localization in a cell cycle-dependent manner. Mimicking constitutive phosphorylation of either CENP-L or CENP-N or simultaneously preventing phosphorylation of both proteins prevents CENP-LN localization and disrupts chromosome segregation. Together, our work suggests that cycles of phosphorylation and dephosphorylation are critical for CENP-LN complex recruitment and dynamics at centromeres to enable cell cycle-dependent CCAN reorganization.

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Cell cycle S-phase arrest drives cell extrusion

10.1101/839845 ◽

2019 ◽

Cited By ~ 1

Author(s):

Vivek K. Dwivedi ◽

Carlos Pardo-Pastor ◽

Rita Droste ◽

Daniel P. Denning ◽

Jody Rosenblatt ◽

...

Keyword(s):

Cell Cycle ◽

S Phase ◽

C Elegans ◽

Phase Arrest ◽

Genome Wide ◽

S Phase Arrest ◽

Epithelial Cultures ◽

A Cell ◽

Cycle Dependent ◽

Cell Extrusion

SUMMARYCell extrusion is a process of cell elimination in which a cell is squeezed out from its tissue of origin. Extrusion occurs in organisms as diverse as sponges, nematodes, insects, fish and mammals. Defective extrusion is linked to many epithelial disorders, including cancer. Despite broad occurrence, cell-intrinsic triggers of extrusion conserved across phyla are generally unknown. We combined genome-wide genetic screens with live-imaging studies of C. elegans embryos and mammalian epithelial cultures and found that S-phase arrest induced extrusion in both. Cells extruded from C. elegans embryos exhibited S-phase arrest, and RNAi treatments that specifically prevent S-phase entry or arrest blocked cell extrusion. Pharmacological induction of S-phase arrest was sufficient to promote cell extrusion from a canine epithelial monolayer. Thus, we have discovered an evolutionarily conserved cell-cycle-dependent trigger of cell extrusion. We suggest that S-phase-arrest induced cell extrusion plays a key role in physiology and disease.

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Topoisomerase IIα Prevents, But Does Not Resolve, Ultrafine Anaphase Bridges By Two Mechanisms

10.1101/815001 ◽

2019 ◽

Author(s):

Simon Gemble ◽

Géraldine Buhagiar-Labarchède ◽

Rosine Onclercq-Delic ◽

Sarah Lambert ◽

Mounira Amor-Guéret

Keyword(s):

Cell Cycle ◽

Dna Replication ◽

S Phase ◽

Cycle Phase ◽

Dependent Manner ◽

Topoisomerase Iiα ◽

Anaphase Bridges ◽

Double Stranded Dna ◽

A Cell ◽

Cycle Dependent

AbstractTopoisomerase IIα (Topo IIα), a well-conserved double-stranded DNA (dsDNA)-specific decatenase, processes dsDNA catenanes resulting from DNA replication during mitosis. Topo IIα defects lead to an accumulation of ultrafine anaphase bridges (UFBs), a type of chromosome non-disjunction. Topo IIα has been reported to resolve DNA anaphase threads, possibly accounting for the increase in UFB frequency upon Topo IIα inhibition. We hypothesized that the excess UFBs might also result, at least in part, from an impairment of the prevention of UFB formation by Topo IIα. We found that Topo IIα inhibition promotes UFB formation without affecting UFB resolution during anaphase. Moreover, we showed that Topo IIα inhibition promotes the formation of two types of UFBs depending on cell-cycle phase. Topo IIα inhibition during S-phase compromises complete DNA replication, leading to the formation of UFB-containing unreplicated DNA, whereas Topo IIα inhibition during mitosis impedes DNA decatenation at metaphase-anaphase transition, leading to the formation of UFB-containing DNA catenanes. Thus, Topo IIα activity is essential to prevent UFB formation in a cell-cycle dependent manner, but dispensable for UFB resolution during anaphase.

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Cell cycle-associated accumulation of tissue inhibitor of metalloproteinases-1 (TIMP-1) in the nuclei of human gingival fibroblasts

Journal of Cell Science ◽

10.1242/jcs.111.9.1147 ◽

1998 ◽

Vol 111 (9) ◽

pp. 1147-1153

Author(s):

W.Q. Zhao ◽

H. Li ◽

K. Yamashita ◽

X.K. Guo ◽

T. Hoshino ◽

...

Keyword(s):

Cell Cycle ◽

Calf Serum ◽

Nuclear Extract ◽

S Phase ◽

Human Gingival Fibroblasts ◽

Dependent Manner ◽

Gingival Fibroblasts ◽

A Cell ◽

Cycle Dependent ◽

Sandwich Enzyme Immunoassay

We first confirmed an earlier immunohistochemical study showing that immunoreactive TIMP-1-like protein accumulated in the nuclei of human gingival fibroblasts (Gin-1 cells), reaching a maximum in the S phase of the cell cycle (Li, H., Nishio, K., Yamashita, K., Hayakawa, T. and Hoshino, T. (1995). Nagoya J. Med. Sci. 58, 133–142). Then we isolated this protein from a nuclear extract of Gin-1 cells and demonstrated it to be identical to human recombinant TIMP-1 by western blotting, by a sandwich enzyme immunoassay for TIMP-1 and by an assay for matrix metalloproteinase inhibition. The amount of TIMP-1 in the cytosolic fraction of quiescent Gin-1 cells after stimulation by fetal calf serum increased continuously for 48 hours, whereas that in the nuclear extract showed a maximum at 24 hours (S phase) and significantly decreased thereafter. Gin-1 cells expressed mRNAs for both TIMP-2 and TIMP-3 together with mRNA for TIMP-1. However, neither TIMP-2 nor TIMP-3 proteins seemed to accumulate in the nuclei of Gin-1 cells. These facts strongly suggest that TIMP-1 accumulates specifically in the nuclei of Gin-1 cells in a cell cycle-dependent manner.

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Faculty Opinions recommendation of A cell cycle-dependent regulatory circuit composed of 53BP1-RIF1 and BRCA1-CtIP controls DNA repair pathway choice.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.717972354.793478994 ◽

2013 ◽

Author(s):

Carol MacKintosh

Keyword(s):

Cell Cycle ◽

Dna Repair ◽

Repair Pathway ◽

Regulatory Circuit ◽

A Cell ◽

Pathway Choice ◽

Cycle Dependent

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Cell cycle–dependent localization of macroH2A in chromatin of the inactive X chromosome

The Journal of Cell Biology ◽

10.1083/jcb.200112074 ◽

2002 ◽

Vol 157 (7) ◽

pp. 1113-1123 ◽

Cited By ~ 74

Author(s):

Brian P. Chadwick ◽

Huntington F. Willard

Keyword(s):

Cell Cycle ◽

X Chromosome ◽

Degradation Pathway ◽

S Phase ◽

Histone H2a ◽

The Core ◽

Inactive X Chromosome ◽

Inactivation Center ◽

Chromatin Proteins ◽

Cycle Dependent

One of several features acquired by chromatin of the inactive X chromosome (Xi) is enrichment for the core histone H2A variant macroH2A within a distinct nuclear structure referred to as a macrochromatin body (MCB). In addition to localizing to the MCB, macroH2A accumulates at a perinuclear structure centered at the centrosome. To better understand the association of macroH2A1 with the centrosome and the formation of an MCB, we investigated the distribution of macroH2A1 throughout the somatic cell cycle. Unlike Xi-specific RNA, which associates with the Xi throughout interphase, the appearance of an MCB is predominantly a feature of S phase. Although the MCB dissipates during late S phase and G2 before reforming in late G1, macroH2A1 remains associated during mitosis with specific regions of the Xi, including at the X inactivation center. This association yields a distinct macroH2A banding pattern that overlaps with the site of histone H3 lysine-4 methylation centered at the DXZ4 locus in Xq24. The centrosomal pool of macroH2A1 accumulates in the presence of an inhibitor of the 20S proteasome. Therefore, targeting of macroH2A1 to the centrosome is likely part of a degradation pathway, a mechanism common to a variety of other chromatin proteins.

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