scholarly journals Retinoblastoma Tumor Suppressor Protein Roles in Epigenetic Regulation

Cancers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2807
Author(s):  
Frederick Guzman ◽  
Yasamin Fazeli ◽  
Meagan Khuu ◽  
Kelsey Salcido ◽  
Sarah Singh ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Epigenetic Regulation ◽  
Cell Cycle Progression ◽  
Cell Cycle Exit ◽  
Loss Of Function ◽  
Cycle Progression ◽  
Retinoblastoma Tumor Suppressor Protein ◽  
Retinoblastoma Tumor Suppressor ◽  
Non Coding Rnas ◽  
Retinoblastoma Tumor

Mutations that result in the loss of function of pRB were first identified in retinoblastoma and since then have been associated with the propagation of various forms of cancer. pRB is best known for its key role as a transcriptional regulator during cell cycle exit. Beyond the ability of pRB to regulate transcription of cell cycle progression genes, pRB can remodel chromatin to exert several of its other biological roles. In this review, we discuss the diverse functions of pRB in epigenetic regulation including nucleosome mobilization, histone modifications, DNA methylation and non-coding RNAs.

scholarly journals Retinoblastoma tumor suppressor protein–dependent methylation of histone H3 lysine 27 is associated with irreversible cell cycle exit

2007 ◽  
Vol 179 (7) ◽  
pp. 1399-1412 ◽  
Author(s):  
Alexandre Blais ◽  
Chris J.C. van Oevelen ◽  
Raphaël Margueron ◽  
Diego Acosta-Alvear ◽  
Brian David Dynlacht
Keyword(s):  
Cell Cycle ◽  
Tumor Suppressor ◽  
Histone H3 ◽  
Tumor Suppressor Protein ◽  
Dependent Manner ◽  
Cell Cycle Exit ◽  
Retinoblastoma Tumor Suppressor Protein ◽  
Retinoblastoma Tumor Suppressor ◽  
Permanent Cell ◽  
Retinoblastoma Tumor

The retinoblastoma tumor suppressor protein (pRb) is involved in mitotic exit, promoting the arrest of myoblasts, and myogenic differentiation. However, it is unclear how permanent cell cycle exit is maintained in differentiated muscle. Using RNA interference, expression profiling, and chromatin immunoprecipitations, we show that pRb is essential for cell cycle exit and the differentiation of myoblasts and is also uniquely required to maintain this arrest in myotubes. Remarkably, we also uncover a function for the pRb-related proteins p107 and p130 as enforcers of a G2/M phase checkpoint that prevents progression into mitosis in cells that have lost pRb. We further demonstrate that pRb effects permanent cell cycle exit in part by maintaining trimethylation of histone H3 lysine 27 (H3K27) on cell cycle genes. H3K27 trimethylation silences other genes, including Cyclin D1, in a pRb-independent but polycomb-dependent manner. Thus, our data distinguish two distinct chromatin-based regulatory mechanisms that lead to terminal differentiation.

scholarly journals Identification of G1 kinase activity for cdk6, a novel cyclin D partner.

1994 ◽  
Vol 14 (3) ◽  
pp. 2077-2086 ◽  
Author(s):  
M Meyerson ◽  
E Harlow
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Kinase Activity ◽  
Suppressor Gene ◽  
Cyclin Dependent Kinase ◽  
Cycle Progression ◽  
Retinoblastoma Tumor Suppressor ◽  
Cell Extracts ◽  
Retinoblastoma Tumor ◽  
Cycle Regulation

A family of vertebrate cdc2-related kinases has been identified, and these kinases are candidates for roles in cell cycle regulation. Here, we show that the human PLSTIRE gene product is a novel cyclin-dependent kinase, cdk6. The cdk6 kinase is associated with cyclins D1, D2, and D3 in lysates of human cells and is activated by coexpression with D-type cyclins in Sf9 insect cells. Furthermore, we demonstrate that endogenous cdk6 from human cell extracts is an active kinase which can phosphorylate pRB, the product of the retinoblastoma tumor suppressor gene. The activation of cdk6 kinase occurs during mid-G1 in phytohemagglutinin-stimulated T cells, well prior to the activation of cdk2 kinase. This timing suggests that cdk6, and by analogy its homolog cdk4, links growth factor stimulation with the onset of cell cycle progression.

Identification of G1 kinase activity for cdk6, a novel cyclin D partner

1994 ◽  
Vol 14 (3) ◽  
pp. 2077-2086
Author(s):  
M Meyerson ◽  
E Harlow
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Kinase Activity ◽  
Suppressor Gene ◽  
Cyclin Dependent Kinase ◽  
Cycle Progression ◽  
Retinoblastoma Tumor Suppressor ◽  
Cell Extracts ◽  
Retinoblastoma Tumor ◽  
Cycle Regulation

A family of vertebrate cdc2-related kinases has been identified, and these kinases are candidates for roles in cell cycle regulation. Here, we show that the human PLSTIRE gene product is a novel cyclin-dependent kinase, cdk6. The cdk6 kinase is associated with cyclins D1, D2, and D3 in lysates of human cells and is activated by coexpression with D-type cyclins in Sf9 insect cells. Furthermore, we demonstrate that endogenous cdk6 from human cell extracts is an active kinase which can phosphorylate pRB, the product of the retinoblastoma tumor suppressor gene. The activation of cdk6 kinase occurs during mid-G1 in phytohemagglutinin-stimulated T cells, well prior to the activation of cdk2 kinase. This timing suggests that cdk6, and by analogy its homolog cdk4, links growth factor stimulation with the onset of cell cycle progression.

SCL-mediated regulation of the cell-cycle regulator p21 is critical for murine megakaryopoiesis

Blood ◽  
2011 ◽  
Vol 118 (3) ◽  
pp. 723-735 ◽  
Author(s):  
Hedia Chagraoui ◽  
Mira Kassouf ◽  
Sreemoti Banerjee ◽  
Nicolas Goardon ◽  
Kevin Clark ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Transcriptional Control ◽  
Cell Cycle Progression ◽  
Cellular Proliferation ◽  
Loss Of Function ◽  
Cycle Progression ◽  
Cell Cycle Regulator ◽  
Nuclear Changes ◽  
Cytoplasmic Maturation

Abstract Megakaryopoiesis is a complex process that involves major cellular and nuclear changes and relies on controlled coordination of cellular proliferation and differentiation. These mechanisms are orchestrated in part by transcriptional regulators. The key hematopoietic transcription factor stem cell leukemia (SCL)/TAL1 is required in early hematopoietic progenitors for specification of the megakaryocytic lineage. These early functions have, so far, prevented full investigation of its role in megakaryocyte development in loss-of-function studies. Here, we report that SCL critically controls terminal megakaryocyte maturation. In vivo deletion of Scl specifically in the megakaryocytic lineage affects all key attributes of megakaryocyte progenitors (MkPs), namely, proliferation, ploidization, cytoplasmic maturation, and platelet release. Genome-wide expression analysis reveals increased expression of the cell-cycle regulator p21 in Scl-deleted MkPs. Importantly, p21 knockdown-mediated rescue of Scl-mutant MkPs shows full restoration of cell-cycle progression and partial rescue of the nuclear and cytoplasmic maturation defects. Therefore, SCL-mediated transcriptional control of p21 is essential for terminal maturation of MkPs. Our study provides a mechanistic link between a major hematopoietic transcriptional regulator, cell-cycle progression, and megakaryocytic differentiation.

scholarly journals Ras controls growth, survival and differentiation in the Drosophila eye by different thresholds of MAP kinase activity

Development ◽  
2001 ◽  
Vol 128 (9) ◽  
pp. 1687-1696 ◽  
Author(s):  
K. Halfar ◽  
C. Rommel ◽  
H. Stocker ◽  
E. Hafen
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Kinase Activity ◽  
Photoreceptor Cells ◽  
Loss Of Function ◽  
Cellular Functions ◽  
Partial Loss ◽  
Cycle Progression ◽  
Mapk Activity ◽  
Dividing Cells

Ras mediates a plethora of cellular functions during development. In the developing eye of Drosophila, Ras performs three temporally separate functions. In dividing cells, it is required for growth but is not essential for cell cycle progression. In postmitotic cells, it promotes survival and subsequent differentiation of ommatidial cells. In the present paper, we have analyzed the different roles of Ras during eye development by using molecularly defined complete and partial loss-of-function mutations of Ras. We show that the three different functions of Ras are mediated by distinct thresholds of MAPK activity. Low MAPK activity prolongs cell survival and permits differentiation of R8 photoreceptor cells while high or persistent MAPK activity is sufficient to precociously induce R1-R7 photoreceptor differentiation in dividing cells.

scholarly journals The RASSF6 Tumor Suppressor Protein Regulates Apoptosis and Cell Cycle Progression via Retinoblastoma Protein

2018 ◽  
Vol 38 (17) ◽  
Author(s):  
Shakhawoat Hossain ◽  
Hiroaki Iwasa ◽  
Aradhan Sarkar ◽  
Junichi Maruyama ◽  
Kyoko Arimoto-Matsuzaki ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Tumor Suppressor ◽  
Cell Cycle Arrest ◽  
Cell Cycle Progression ◽  
Target Genes ◽  
Loss Of Function ◽  
Cycle Progression ◽  
P53 Expression ◽  
Cycle Arrest ◽  
Hct116 Cells

ABSTRACT RASSF6 is a member of the tumor suppressor Ras association domain family (RASSF) proteins. RASSF6 is frequently suppressed in human cancers, and its low expression level is associated with poor prognosis. RASSF6 regulates cell cycle arrest and apoptosis and plays a tumor suppressor role. Mechanistically, RASSF6 blocks MDM2-mediated p53 degradation and enhances p53 expression. However, RASSF6 also induces cell cycle arrest and apoptosis in a p53-negative background, which implies that the tumor suppressor function of RASSF6 does not depend solely on p53. In this study, we revealed that RASSF6 mediates cell cycle arrest and apoptosis via pRb. RASSF6 enhances the interaction between pRb and protein phosphatase. RASSF6 also enhances P16INK4A and P14ARF expression by suppressing BMI1. In this way, RASSF6 increases unphosphorylated pRb and augments the interaction between pRb and E2F1. Moreover, RASSF6 induces TP73 target genes via pRb and E2F1 in a p53-negative background. Finally, we confirmed that RASSF6 depletion induces polyploid cells in p53-negative HCT116 cells. In conclusion, RASSF6 behaves as a tumor suppressor in cancers with loss of function of p53, and pRb is implicated in this function of RASSF6.

scholarly journals MicroRNAs in the miR-106b Family Regulate p21/CDKN1A and Promote Cell Cycle Progression

2008 ◽  
Vol 28 (7) ◽  
pp. 2167-2174 ◽  
Author(s):  
Irena Ivanovska ◽  
Alexey S. Ball ◽  
Robert L. Diaz ◽  
Jill F. Magnus ◽  
Miho Kibukawa ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Kinase Inhibitor ◽  
Phenotype Microarray ◽  
Loss Of Function ◽  
Cycle Progression ◽  
Multiple Tumor ◽  
Cyclin Dependent Kinase Inhibitor ◽  
Expression Of Genes ◽  
Tumor Types

ABSTRACT microRNAs in the miR-106b family are overexpressed in multiple tumor types and are correlated with the expression of genes that regulate the cell cycle. Consistent with these observations, miR-106b family gain of function promotes cell cycle progression, whereas loss of function reverses this phenotype. Microarray profiling uncovers multiple targets of the family, including the cyclin-dependent kinase inhibitor p21/CDKN1A. We show that p21 is a direct target of miR-106b and that its silencing plays a key role in miR-106b-induced cell cycle phenotypes. We also show that miR-106b overrides a doxorubicin-induced DNA damage checkpoint. Thus, miR-106b family members contribute to tumor cell proliferation in part by regulating cell cycle progression and by modulating checkpoint functions.

scholarly journals The RASSF6 tumor suppressor protein regulates apoptosis and the cell cycle progression via Retinoblastoma protein

2018 ◽  
Author(s):  
Shakhawoat Hossain ◽  
Hiroaki Iwasa ◽  
Aradhan Sarkar ◽  
Junichi Maruyama ◽  
Kyoko Arimoto-Matsuzaki ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Tumor Suppressor ◽  
Cell Cycle Arrest ◽  
Cell Cycle Progression ◽  
Target Genes ◽  
Loss Of Function ◽  
Cycle Progression ◽  
P53 Expression ◽  
Cycle Arrest ◽  
Hct116 Cells

ABSTRACTRASSF6 is a member of the tumor suppressor Ras-association domain family (RASSF) proteins. RASSF6 is frequently suppressed in human cancers and its low expression is associated with poor prognosis. RASSF6 regulates cell cycle arrest and apoptosis and plays a tumor suppressor role. Mechanistically, RASSF6 blocks MDM2-mediated p53 degradation and enhances p53 expression. However, RASSF6 also induces cell cycle arrest and apoptosis in the p53-negative background, which implies that the tumor suppressor function of RASSF6 does not depend solely on p53. In this study, we have revealed that RASSF6 mediates cell cycle arrest and apoptosis via pRb. RASSF6 enhances the interaction between pRb and protein phosphatase. RASSF6 also enhances P16INK4A and P14ARF expression through suppressing BMI1. In this way, RASSF6 increases unphosphorylated pRb and augments the interaction between pRb and E2F1. Moreover, RASSF6 induces TP73-target genes via pRb and E2F1 in the p53-negative background. Finally, we confirmed that RASSF6 depletion induces polypoid cells in p53-negative HCT116 cells. In conclusion, RASSF6 behaves as a tumor suppressor in cancers with the loss-of-function of p53, and pRb is implicated in this function of RASSF6.

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