scholarly journals Satb2 regulates proliferation and nuclear integrity of pre-osteoblasts

2019 ◽  
Author(s):  
Todd Dowrey ◽  
Evelyn E. Schwager ◽  
Julieann Duong ◽  
Fjodor Merkuri ◽  
Yuri A. Zarate ◽  
...  

AbstractSpecial AT-rich sequence binding protein 2 (Satb2) is a matrix attachment region (MAR) binding protein. Satb2 impacts skeletal development by regulating gene transcription required for osteogenic differentiation. Although its role as a high-order transcription factor is well supported, other roles for Satb2 in skeletal development remain unclear. In particular, the impact of dosage sensitivity (heterozygous mutations) and variance on phenotypic severity is still not well understood. To further investigate molecular and cellular mechanisms of Satb2-mediated skeletal defects, we used the CRISPR/Cas9 system to generate Satb2 mutations in MC3T3-E1 cells. Our data suggest that, in addition to its role in differentiation, Satb2 regulates progenitor proliferation. We also find that mutations in Satb2 cause chromatin defects including nuclear blebbing and donut-shaped nuclei. These defects may contribute to a slight increase in apoptosis in mutant cells, but apoptosis is insufficient to explain the proliferation defects. Satb2 expression exhibits population-level variation and is mostly highly expressed from late G1 to late G2. Based on these data, we hypothesize that Satb2 may regulate proliferation through two separate mechanisms. First, Satb2 may regulate the expression of genes necessary for cell cycle progression in pre-osteoblasts. Second, similar to other MAR-binding proteins, Satb2 may participate in DNA replication. Deficiencies in either of these processes could reduce the pace of cell cycle progression and contribute to nuclear damage. We also hypothesize that Satb2-mediated proliferation defects may be buffered in some genetic backgrounds, which provides some explanation for differences in severity of skeletal defects. Further elucidation of the role of Satb2 in proliferation has potential impacts on our understanding of both skeletal defects and cancer.




1999 ◽  
Vol 146 (2) ◽  
pp. 373-387 ◽  
Author(s):  
Jana Drgonová ◽  
Tomás Drgon ◽  
Dong-Hyun Roh ◽  
Enrico Cabib

Previous work showed that the GTP-binding protein Rho1p is required in the yeast, Saccharomyces cerevisiae, for activation of protein kinase C (Pkc1p) and for activity and regulation of β(1→3)glucan synthase. Here we demonstrate a hitherto unknown function of Rho1p required for cell cycle progression and cell polarization. Cells of mutant rho1E45I in the G1 stage of the cell cycle did not bud at 37°C. In those cells actin reorganization and recruitment to the presumptive budding site did not take place at the nonpermissive temperature. Two mutants in adjacent amino acids, rho1V43T and rho1F44Y, showed a similar behavior, although some budding and actin polarization occurred at the nonpermissive temperature. This was also the case for rho1E45I when placed in a different genetic background. Cdc42p and Spa2p, two proteins that normally also move to the bud site in a process independent from actin organization, failed to localize properly in rho1E45I. Nuclear division did not occur in the mutant at 37°C, although replication of DNA proceeded slowly. The rho1 mutants were also defective in the formation of mating projections and in congregation of actin at the projections in the presence of mating pheromone. The in vitro activity of β(1→3)glucan synthase in rho1 E45I, although diminished at 37°C, appeared sufficient for normal in vivo function and the budding defect was not suppressed by expression of a constitutively active allele of PKC1. Reciprocally, when Pkc1p function was eliminated by the use of a temperature-sensitive mutation and β(1→3)glucan synthesis abolished by an echinocandin-like inhibitor, a strain carrying a wild-type RHO1 allele was able to produce incipient buds. Taken together, these results reveal a novel function of Rho1p that must be executed in order for the yeast cell to polarize.



2018 ◽  
Vol 69 (4) ◽  
pp. 622-635.e6 ◽  
Author(s):  
Cindy Meyer ◽  
Aitor Garzia ◽  
Michael Mazzola ◽  
Stefanie Gerstberger ◽  
Henrik Molina ◽  
...  


2019 ◽  
Vol 61 ◽  
pp. 35-43
Author(s):  
Hongli Jiang ◽  
Jie Li ◽  
Xin He ◽  
Jinhong Xue ◽  
Shanshan Liang ◽  
...  


PLoS Genetics ◽  
2013 ◽  
Vol 9 (3) ◽  
pp. e1003367 ◽  
Author(s):  
Laetitia Davidovic ◽  
Nelly Durand ◽  
Olfa Khalfallah ◽  
Ricardo Tabet ◽  
Pascal Barbry ◽  
...  


2021 ◽  
Author(s):  
Julia S Spear ◽  
Katharine A White

Transient changes in intracellular pH (pHi) have been shown to regulate normal cell behaviors like migration and cell-cycle progression, while dysregulated pHi dynamics are a hallmark of cancer. However, little is known about how pHi heterogeneity and dynamics influence population-level measurements or single-cell behaviors. Here, we present and characterize single-cell pHi heterogeneity distributions in both normal and cancer cells and measure dynamic pHi increases in single cells in response to growth factor signaling. Next, we measure pHi dynamics in single cells during cell cycle progression. We determined that single-cell pHi is significantly decreased at the G1/S boundary, increases from S phase to the G2/M transition, rapidly acidifies during mitosis, and recovers in daughter cells. This sinusoidal pattern of pHi dynamics was linked to cell cycle timing regardless of synchronization method. This work confirms prior work at the population level and reveals distinct advantages of single-cell pHi measurements in capturing pHi heterogeneity across a population and dynamics within single cells.



2006 ◽  
Vol 20 (5) ◽  
Author(s):  
Rebecca Claire Chiffer ◽  
Sara K. Snyder ◽  
Pedro Rodriguez ◽  
Eric Anderson ◽  
Catharine L. Smith


2010 ◽  
Vol 38 (2) ◽  
pp. 577-582 ◽  
Author(s):  
Michael Borg ◽  
David Twell

Pollen grains represent the highly reduced haploid male gametophyte generation in angiosperms. They play an essential role in plant fertility by generating and delivering twin sperm cells to the embryo sac to undergo double fertilization. The functional specialization of the male gametophyte and double fertilization are considered to be key innovations in the evolutionary success of angiosperms. The haploid nature of the male gametophyte and its highly tractable ontogeny makes it an attractive system to study many fundamental biological processes, such as cell fate determination, cell-cycle progression and gene regulation. The present mini-review encompasses key advances in our understanding of the molecular mechanisms controlling male gametophyte patterning in angiosperms. A brief overview of male gametophyte development is presented, followed by a discussion of the genes required at landmark events of male gametogenesis. The value of the male gametophyte as an experimental system to study the interplay between cell fate determination and cell-cycle progression is also discussed and exemplified with an emerging model outlining the regulatory networks that distinguish the fate of the male germline from its sister vegetative cell. We conclude with a perspective of the impact emerging data will have on future research strategies and how they will develop further our understanding of male gametogenesis and plant development.



2014 ◽  
Vol 307 (11) ◽  
pp. G1073-G1087 ◽  
Author(s):  
Bryan C. Tackett ◽  
Hongdan Sun ◽  
Yu Mei ◽  
Janielle P. Maynard ◽  
Sayuri Cheruvu ◽  
...  

Extracellular nucleotides via activation of P2 purinergic receptors influence hepatocyte proliferation and liver regeneration in response to 70% partial hepatectomy (PH). Adult hepatocytes express multiple P2Y (G protein-coupled) and P2X (ligand-gated ion channels) purinergic receptor subtypes. However, the identity of key receptor subtype(s) important for efficient hepatocyte proliferation in regenerating livers remains unknown. To evaluate the impact of P2Y2 purinergic receptor-mediated signaling on hepatocyte proliferation in regenerating livers, wild-type (WT) and P2Y2 purinergic receptor knockout (P2Y2−/−) mice were subjected to 70% PH. Liver tissues were analyzed for activation of early events critical for hepatocyte priming and subsequent cell cycle progression. Our findings suggest that early activation of p42/44 ERK MAPK (5 min), early growth response-1 (Egr-1) and activator protein-1 (AP-1) DNA-binding activity (30 min), and subsequent hepatocyte proliferation (24–72 h) in response to 70% PH were impaired in P2Y2−/− mice. Interestingly, early induction of cytokines (TNF-α, IL-6) and cytokine-mediated signaling (NF-κB, STAT-3) were intact in P2Y2−/− remnant livers, uncovering the importance of cytokine-independent and nucleotide-dependent early priming events critical for subsequent hepatocyte proliferation in regenerating livers. Hepatocytes isolated from the WT and P2Y2−/− mice were treated with ATP or ATPγS for 5–120 min and 12–24 h. Extracellular ATP alone, via activation of P2Y2 purinergic receptors, was sufficient to induce ERK phosphorylation, Egr-1 protein expression, and key cyclins and cell cycle progression of hepatocytes in vitro. Collectively, these findings highlight the functional significance of P2Y2 purinergic receptor activation for efficient hepatocyte priming and proliferation in response to PH.



FEBS Letters ◽  
1995 ◽  
Vol 370 (1-2) ◽  
pp. 27-31 ◽  
Author(s):  
S. Mian ◽  
S. El Alaoui ◽  
J. Lawry ◽  
V. Gentile ◽  
P.J.A. Davies ◽  
...  


Sign in / Sign up

Export Citation Format

Share Document