scholarly journals Cyclin-dependent kinases govern formation and maintenance of the nucleolus

2002 ◽  
Vol 156 (6) ◽  
pp. 969-981 ◽  
Author(s):  
Valentina Sirri ◽  
Danièle Hernandez-Verdun ◽  
Pascal Roussel
Keyword(s):  
Cell Cycle ◽  
Ribosome Biogenesis ◽  
Rrna Processing ◽  
Cell Cycle Regulators ◽  
Rdna Transcription ◽  
Nuclear Compartment ◽  
Cyclin Dependent Kinases ◽  
Processing Machinery ◽  
Transcription Sites

In higher eukaryotic cells, the nucleolus is a nuclear compartment assembled at the beginning of interphase, maintained during interphase, and disorganized during mitosis. Even if its structural organization appears to be undissociable from its function in ribosome biogenesis, the mechanisms that govern the formation and maintenance of the nucleolus are not elucidated. To determine if cell cycle regulators are implicated, we investigated the putative role of the cyclin-dependent kinases (CDKs) on ribosome biogenesis and nucleolar organization. Inhibition of CDK1–cyclin B during mitosis leads to resumption of rDNA transcription, but is not sufficient to induce proper processing of the pre-rRNA and total relocalization of the processing machinery into rDNA transcription sites. Similarly, at the exit from mitosis, both translocation of the late processing machinery and pre-rRNA processing are impaired in a reversible manner by CDK inhibitors. Therefore, CDK activity seems indispensable for the building of functional nucleoli. Furthermore, inhibition of CDKs in interphasic cells also hampered proper pre-rRNA processing and induced a dramatic disorganization of the nucleolus. Thus, we propose that the mechanisms governing both formation and maintenance of functional nucleoli involve CDK activities and couple the cell cycle to ribosome biogenesis.

scholarly journals MicroRNAs Determining Carcinogenesis by Regulating Oncogenes and Tumor Suppressor Genes During Cell Cycle

MicroRNA ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 82-92 ◽  
Author(s):  
Fasoulakis Zacharias ◽  
Daskalakis George ◽  
Diakosavvas Michail ◽  
Papapanagiotou Ioannis ◽  
Theodora Marianna ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Tumor Suppressor ◽  
Tumor Suppressor Genes ◽  
Cancer Development ◽  
Cell Cycle Regulators ◽  
Suppressor Genes ◽  
Cyclin Dependent Kinases ◽  
Multiple Cell ◽  
Therapeutic Tools

Aim:: To provide a review considering microRNAs regulating oncogenes and tumor suppressor genes during the different stages of cell cycle, controlling carcinogenesis. Methods:: The role of microRNAs involved as oncogenes’ and tumor suppressor genes’ regulators in cancer was searched in the relevant available literature in MEDLINE, including terms such as “microRNA”, “oncogenes”, “tumor suppressor genes”, “metastasis”, “cancer” and others. Results:: MicroRNAs determine the expression levels of multiple cell cycle regulators, such as cyclins, cyclin dependent kinases and other major cell cycle activators including retinoblastoma 1 (RB- 1) and p53, resulting in alteration and promotion/inhibition of the cell cycle. Conclusion:: MicroRNAs are proven to have a key role in cancer pathophysiology by altering the expression profile of different regulator proteins during cell division cycle and DNA replication. Thus, by acting as oncogenes and tumor suppressor genes, they can either promote or inhibit cancer development and formation, revealing their innovative role as biomarkers and therapeutic tools.

Biological Role of CDK 11 and 12 in Cell Cycle and its Function in Tumorigenesis

2020 ◽  
Author(s):  
Shamim Mushtaq
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Web Of Science ◽  
The Body ◽  
Main Role ◽  
Hallmarks Of Cancer ◽  
Cyclin Dependent Kinases ◽  
Tumor Studies ◽  
Cycle Regulation

Uninhibited proliferation and abnormal cell cycle regulation are the hallmarks of cancer. The main role of cyclin dependent kinases is to regulate the cell cycle and cell proliferation. These protein kinases are frequently down regulated or up regulated in various cancers. Two CDK family members, CDK 11 and 12, have contradicting views about their roles in different cancers. For example, one study suggests that the CDK 11 isoforms, p58, inhibits growth of breast cancer whereas, the CDK 11 isoform, p110, is highly expressed in breast tumor. Studies regarding CDK 12 show variation of opinion towards different parts of the body, however there is a consensus that upregulation of cdk12 increases the risk of breast cancer. Hence, CDK 11 and CDK 12 need to be analyzed to confirm their mechanism and their role regarding therapeutics, prognostic value, and ethnicity in cancer. This article gives an outline on both CDKs of information known up to date from Medline, PubMed, Google Scholar and Web of Science search engines, which were explored and thirty relevant researches were finalized.

scholarly journals The possible role of cell cycle regulators in multistep process of HPV-associated cervical carcinoma

2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Abeer A Bahnassy ◽  
Abdel Rahman N Zekri ◽  
Maha Saleh ◽  
Mohammad Lotayef ◽  
Manar Moneir ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cervical Carcinoma ◽  
Cell Cycle Regulators ◽  
Multistep Process

scholarly journals Intricate Regulatory Mechanisms of the Anaphase-Promoting Complex/Cyclosome and Its Role in Chromatin Regulation

2021 ◽  
Vol 9 ◽  
Author(s):  
Tatyana Bodrug ◽  
Kaeli A. Welsh ◽  
Megan Hinkle ◽  
Michael J. Emanuele ◽  
Nicholas G. Brown
Keyword(s):  
Cell Cycle ◽  
Signaling Pathways ◽  
Biological Process ◽  
Conformational Dynamics ◽  
Intimate Relationship ◽  
Regulatory Mechanisms ◽  
Cell Cycle Regulators ◽  
Chromatin Regulation ◽  
Anaphase Promoting Complex

The ubiquitin (Ub)-proteasome system is vital to nearly every biological process in eukaryotes. Specifically, the conjugation of Ub to target proteins by Ub ligases, such as the Anaphase-Promoting Complex/Cyclosome (APC/C), is paramount for cell cycle transitions as it leads to the irreversible destruction of cell cycle regulators by the proteasome. Through this activity, the RING Ub ligase APC/C governs mitosis, G1, and numerous aspects of neurobiology. Pioneering cryo-EM, biochemical reconstitution, and cell-based studies have illuminated many aspects of the conformational dynamics of this large, multi-subunit complex and the sophisticated regulation of APC/C function. More recent studies have revealed new mechanisms that selectively dictate APC/C activity and explore additional pathways that are controlled by APC/C-mediated ubiquitination, including an intimate relationship with chromatin regulation. These tasks go beyond the traditional cell cycle role historically ascribed to the APC/C. Here, we review these novel findings, examine the mechanistic implications of APC/C regulation, and discuss the role of the APC/C in previously unappreciated signaling pathways.

scholarly journals Arabidopsis small nucleolar RNA monitors the efficient pre-rRNA processing during ribosome biogenesis

2016 ◽  
Vol 113 (42) ◽  
pp. 11967-11972 ◽  
Author(s):  
Pan Zhu ◽  
Yuqiu Wang ◽  
Nanxun Qin ◽  
Feng Wang ◽  
Jia Wang ◽  
...  
Keyword(s):  
Ribosome Biogenesis ◽  
Higher Plants ◽  
Ribosomal Subunit ◽  
Rrna Processing ◽  
Developmental Defects ◽  
Protein Mutants ◽  
5.8S Rrna ◽  
Important Regulator ◽  
Nucleolar Rna

Ribosome production in eukaryotes requires the complex and precise coordination of several hundred assembly factors, including many small nucleolar RNAs (snoRNAs). However, at present, the distinct role of key snoRNAs in ribosome biogenesis remains poorly understood in higher plants. Here we report that a previously uncharacterized C (RUGAUGA)/D (CUGA) type snoRNA, HIDDEN TREASURE 2 (HID2), acts as an important regulator of ribosome biogenesis through a snoRNA–rRNA interaction. Nucleolus-localized HID2 is actively expressed in Arabidopsis proliferative tissues, whereas defects in HID2 cause a series of developmental defects reminiscent of ribosomal protein mutants. HID2 associates with the precursor 45S rRNA and promotes the efficiency and accuracy of pre-rRNA processing. Intriguingly, disrupting HID2 in Arabidopsis appears to impair the integrity of 27SB, a key pre-rRNA intermediate that generates 25S and 5.8S rRNA and is known to be vital for the synthesis of the 60S large ribosomal subunit and also produces an imbalanced ribosome profile. Finally, we demonstrate that the antisense-box of HID2 is both functionally essential and highly conserved in eukaryotes. Overall, our study reveals the vital and possibly conserved role of a snoRNA in monitoring the efficiency of pre-rRNA processing during ribosome biogenesis.

scholarly journals The role of SCF ubiquitin-ligase complex at the beginning of life

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Jiayan Xie ◽  
Yimei Jin ◽  
Guang Wang
Keyword(s):  
Cell Cycle ◽  
Ubiquitin Ligase ◽  
Cellular Proteins ◽  
Cell Cycle Regulators ◽  
Signal Transducers ◽  
E3 Ligases ◽  
Cellular Processes ◽  
Ubiquitin Ligase Complex ◽  
Scf Ubiquitin Ligase

AbstractAs the largest family of E3 ligases, the Skp1-cullin 1-F-box (SCF) E3 ligase complex is comprised of Cullins, Skp1 and F-box proteins. And the SCF E3 ubiquitin ligases play an important role in regulating critical cellular processes, which promote degradation of many cellular proteins, including signal transducers, cell cycle regulators, and transcription factors. We review the biological roles of the SCF ubiquitin-ligase complex in gametogenesis, oocyte-to-embryo transition, embryo development and the regulation for estrogen and progestin. We find that researches about the SCF ubiquitin-ligase complex at the beginning of life are not comprehensive, thus more in-depth researches will promote its eventual clinical application.

CELL CYCLE: The Expanding Role of Cell Cycle Regulators

Science ◽  
1998 ◽  
Vol 280 (5366) ◽  
pp. 1035-1036 ◽  
Author(s):  
T. Jacks
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Regulators
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