scholarly journals Mechanotransduction via the LINC complex regulates DNA replication in myonuclei

2018 ◽  
Vol 217 (6) ◽  
pp. 2005-2018 ◽  
Author(s):  
Shuoshuo Wang ◽  
Elizabeth Stoops ◽  
Unnikannan CP ◽  
Barak Markus ◽  
Adriana Reuveny ◽  
...  

Nuclear mechanotransduction has been implicated in the control of chromatin organization; however, its impact on functional contractile myofibers is unclear. We found that deleting components of the linker of nucleoskeleton and cytoskeleton (LINC) complex in Drosophila melanogaster larval muscles abolishes the controlled and synchronized DNA endoreplication, typical of nuclei across myofibers, resulting in increased and variable DNA content in myonuclei of individual myofibers. Moreover, perturbation of LINC-independent mechanical input after knockdown of β-Integrin in larval muscles similarly led to increased DNA content in myonuclei. Genome-wide RNA-polymerase II occupancy analysis in myofibers of the LINC mutant klar indicated an altered binding profile, including a significant decrease in the chromatin regulator barrier-to-autointegration factor (BAF) and the contractile regulator Troponin C. Importantly, muscle-specific knockdown of BAF led to increased DNA content in myonuclei, phenocopying the LINC mutant phenotype. We propose that mechanical stimuli transmitted via the LINC complex act via BAF to regulate synchronized cell-cycle progression of myonuclei across single myofibers.

2015 ◽  
Vol 35 (21) ◽  
pp. 3753-3767 ◽  
Author(s):  
Connor O'Sullivan ◽  
Jennifer Christie ◽  
Marcus Pienaar ◽  
Jake Gambling ◽  
Philip E. B. Nickerson ◽  
...  

ARS2 is a regulator of RNA polymerase II transcript processing through its role in the maturation of distinct nuclear cap-binding complex (CBC)-controlled RNA families. In this study, we examined ARS2 domain function in transcript processing. Structural modeling based on the plant ARS2 orthologue, SERRATE, revealed 2 previously uncharacterized domains in mammalian ARS2: an N-terminal domain of unknown function (DUF3546), which is also present in SERRATE, and an RNA recognition motif (RRM) that is present in metazoan ARS2 but not in plants. Both the DUF3546 and zinc finger domain (ZnF) were required for association with microRNA and replication-dependent histone mRNA. Mutations in the ZnF disrupted interaction with FLASH, a key component in histone pre-mRNA processing. Mutations targeting the Mid domain implicated it in DROSHA interaction and microRNA biogenesis. The unstructured C terminus was required for interaction with the CBC protein CBP20, while the RRM was required for cell cycle progression and for binding to FLASH. Together, our results support a bridging model in which ARS2 plays a central role in RNA recognition and processing through multiple protein and RNA interactions.


2006 ◽  
Vol 17 (11) ◽  
pp. 4736-4747 ◽  
Author(s):  
Lisa Yu ◽  
Lourdes Peña Castillo ◽  
Sanie Mnaimneh ◽  
Timothy R. Hughes ◽  
Grant W. Brown

Mutations impacting specific stages of cell growth and division have provided a foundation for dissecting mechanisms that underlie cell cycle progression. We have undertaken an objective examination of the yeast cell cycle through flow cytometric analysis of DNA content in TetO7promoter mutant strains representing 75% of all essential yeast genes. More than 65% of the strains displayed specific alterations in DNA content, suggesting that reduced function of an essential gene in most cases impairs progression through a specific stage of the cell cycle. Because of the large number of essential genes required for protein biosynthesis, G1 accumulation was the most common phenotype observed in our analysis. In contrast, relatively few mutants displayed S-phase delay, and most of these were defective in genes required for DNA replication or nucleotide metabolism. G2 accumulation appeared to arise from a variety of defects. In addition to providing a global view of the diversity of essential cellular processes that influence cell cycle progression, these data also provided predictions regarding the functions of individual genes: we identified four new genes involved in protein trafficking (NUS1, PHS1, PGA2, PGA3), and we found that CSE1 and SMC4 are important for DNA replication.


2000 ◽  
Vol 20 (20) ◽  
pp. 7726-7734 ◽  
Author(s):  
Eiji Nishiwaki ◽  
Saralinda L. Turner ◽  
Susanna Harju ◽  
Shiro Miyazaki ◽  
Masahide Kashiwagi ◽  
...  

ABSTRACT The eukaryotic cell cycle is regulated by cyclin-dependent kinases (CDKs). CDK4 and CDK6, which are activated by D-type cyclins during the G1 phase of the cell cycle, are thought to be responsible for phosphorylation of the retinoblastoma gene product (pRb). The tumor suppressor p16INK4A inhibits phosphorylation of pRb by CDK4 and CDK6 and can thereby block cell cycle progression at the G1/S boundary. Phosphorylation of the carboxyl-terminal domain (CTD) of the large subunit of RNA polymerase II by general transcription factor TFIIH is believed to be an important regulatory event in transcription. TFIIH contains a CDK7 kinase subunit and phosphorylates the CTD. We have previously shown that p16INK4A inhibits phosphorylation of the CTD by TFIIH. Here we report that the ability of p16INK4A to inhibit CDK7-CTD kinase contributes to the capacity to induce cell cycle arrest. These results suggest that p16INK4A may regulate cell cycle progression by inhibiting not only CDK4-pRb kinase activity but also by modulating CDK7-CTD kinase activity. Regulation of CDK7-CTD kinase activity by p16INK4A thus may represent an alternative pathway for controlling cell cycle progression.


2020 ◽  
Author(s):  
Jennifer L. Kernan ◽  
Raquel C. Martinez-Chacin ◽  
Xianxi Wang ◽  
Rochelle L. Tiedemann ◽  
Thomas Bonacci ◽  
...  

AbstractThe Anaphase-Promoting Complex/Cyclosome (APC/C) is an E3 ubiquitin ligase and critical regulator of cell cycle progression. Despite its vital role, it has remained challenging to globally map APC/C substrates. By combining orthogonal features of known substrates, we predicted APC/C substrates in silico. This analysis identified many known substrates and suggested numerous candidates. Unexpectedly, chromatin regulatory proteins are enriched among putative substrates and we show that several chromatin proteins bind APC/C, oscillate during the cell cycle and are degraded following APC/C activation, consistent with being direct APC/C substrates. Additional analysis revealed detailed mechanisms of ubiquitylation for UHRF1, a key chromatin regulator involved in histone ubiquitylation and DNA methylation maintenance. Disrupting UHRF1 degradation at mitotic exit accelerates G1-phase cell cycle progression and perturbs global DNA methylation patterning in the genome. We conclude that APC/C coordinates crosstalk between cell cycle and chromatin regulatory proteins. This has potential consequences in normal cell physiology, where the chromatin environment changes depending on proliferative state, as well as in disease.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Longtao Wu ◽  
Clayton D. Crawley ◽  
Andrea Garofalo ◽  
Jackie W. Nichols ◽  
Paige-Ashley Campbell ◽  
...  

Abstract p50, the mature product of NFKB1, is constitutively produced from its precursor, p105. Here, we identify BARD1 as a p50-interacting factor. p50 directly associates with the BARD1 BRCT domains via a C-terminal phospho-serine motif. This interaction is induced by ATR and results in mono-ubiquitination of p50 by the BARD1/BRCA1 complex. During the cell cycle, p50 is mono-ubiquitinated in S phase and loss of this post-translational modification increases S phase progression and chromosomal breakage. Genome-wide studies reveal a substantial decrease in p50 chromatin enrichment in S phase and Cycln E is identified as a factor regulated by p50 during the G1 to S transition. Functionally, interaction with BARD1 promotes p50 protein stability and consistent with this, in human cancer specimens, low nuclear BARD1 protein strongly correlates with low nuclear p50. These data indicate that p50 mono-ubiquitination by BARD1/BRCA1 during the cell cycle regulates S phase progression to maintain genome integrity.


Nature ◽  
2004 ◽  
Vol 432 (7020) ◽  
pp. 980-987 ◽  
Author(s):  
M. Bettencourt-Dias ◽  
R. Giet ◽  
R. Sinka ◽  
A. Mazumdar ◽  
W. G. Lock ◽  
...  

2017 ◽  
Vol 28 (13) ◽  
pp. 1738-1744 ◽  
Author(s):  
Gabor Banyai ◽  
Zsolt Szilagyi ◽  
Vera Baraznenok ◽  
Olga Khorosjutina ◽  
Claes M. Gustafsson

The multiprotein Mediator complex is required for the regulated transcription of nearly all RNA polymerase II–dependent genes. Mediator contains the Cdk8 regulatory subcomplex, which directs periodic transcription and influences cell cycle progression in fission yeast. Here we investigate the role of CycC, the cognate cyclin partner of Cdk8, in cell cycle control. Previous reports suggested that CycC interacts with other cellular Cdks, but a fusion of CycC to Cdk8 reported here did not cause any obvious cell cycle phenotypes. We find that Cdk8 and CycC interactions are stabilized within the Mediator complex and the activity of Cdk8-CycC is regulated by other Mediator components. Analysis of a mutant yeast strain reveals that CycC, together with Cdk8, primarily affects M-phase progression but mutations that release Cdk8 from CycC control also affect timing of entry into S phase.


1993 ◽  
Vol 105 (1) ◽  
pp. 113-122 ◽  
Author(s):  
S. Adolph ◽  
S. Brusselbach ◽  
R. Muller

We have analysed the role of RNA polymerase II-dependent transcription in cell cycle progression. Time-lapse video recording and cytogenetic analysis were used to determine the sensitivity of NIH3T3 cells to the RNA polymerase II inhibitor alpha-amanitin at different stages of the cell cycle. Our results show that alpha-amanitin blocks cells specifically in G1, irrespective of the concentration within the range of 3 to 30 micrograms/ml. This indicates that transcription in G1 is required to overcome a restriction point located in this phase of the cell cycle. In agreement with this conclusion is the requirement for an uninhibited protein synthesis during G1 progression. In addition, the insensitivity of S-phase cells to RNA polymerase II inhibition suggests that the transcription of genes thought to be normally induced during S/G2 is not required for the completion of an ongoing cell cycle. S/G2 progression was however clearly dependent on protein synthesis. This suggests that cells exposed to alpha-amanitin are able to complete their cell cycle because sufficiently high levels of mRNA are present in S/G2 due to basal level transcription, or are left from preceding cell cycles. It is therefore unlikely that transcriptional regulation in S or G2 plays a crucial role in the control of cell cycle progression in NIH3T3 cells.


2021 ◽  
Author(s):  
Helle Samdal ◽  
Siv A. Hegre ◽  
Konika Chawla ◽  
Nina-Beate Liabakk ◽  
Per A. Aas ◽  
...  

AbstractLong noncoding RNAs (lncRNAs) are involved in the regulation of cell cycle, although only a few have been functionally characterized. By combining RNA sequencing and ChIP sequencing of cell cycle synchronized HaCaT cells we have previously identified lncRNAs highly enriched for cell cycle functions. Based on a cyclic expression profile and an overall high correlation to histone 3 lysine 4 trimethylation (H3K4me3) and RNA polymerase II (Pol II) signals, the lncRNA SNHG26 was identified as a top candidate. In the present study we report that downregulation of SNHG26 affects mitochondrial stress, proliferation, cell cycle phase distribution, and gene expression in cis- and in trans, and that this effect is reversed by upregulation of SNHG26. We also find that the effect on cell cycle phase distribution is cell type specific and stable over time. Results indicate an oncogenic role of SNHG26, possibly by affecting cell cycle progression through the regulation of downstream MYC-responsive genes.


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