Poly(ADP-ribosyl)ation is a reversible post-translational modification synthetized by ADP-ribose transferases and removed by poly(ADP-ribose) glycohydrolase (PARG), which plays important roles in DNA damage repair. While well-studied in somatic tissues, much less is known about poly(ADP-ribosyl)ation in the germline, where DNA double-strand breaks are introduced by a regulated program and repaired by crossover recombination to establish a tether between homologous chromosomes. The interaction between the parental chromosomes is facilitated by meiotic specific adaptation of the chromosome axes and cohesins, and reinforced by the synaptonemal complex. Here, we uncover an unexpected role for PARG in coordinating the induction of meiotic DNA breaks and their homologous recombination-mediated repair in Caenorhabditis elegans. PARG-1/PARG interacts with both axial and central elements of the synaptonemal complex, REC-8/Rec8 and the MRN/X complex. PARG-1 shapes the recombination landscape and reinforces the tightly regulated control of crossover numbers without requiring its catalytic activity. We unravel roles in regulating meiosis, beyond its enzymatic activity in poly(ADP-ribose) catabolism.

• MeSH
• buněčné jádro metabolismus   MeSH
• Caenorhabditis elegans genetika   metabolismus   MeSH
• DNA metabolismus   MeSH
• dvouřetězcové zlomy DNA * MeSH
• glykosidhydrolasy genetika   metabolismus   MeSH
• jaderné proteiny genetika   metabolismus   MeSH
• oprava DNA fyziologie   MeSH
• poly-ADP-ribosylace MeSH
• polyadenosindifosfátribosa metabolismus   MeSH
• posttranslační úpravy proteinů MeSH
• proteiny Caenorhabditis elegans genetika   metabolismus   MeSH
• zárodečné buňky MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

The product of the retinoblastoma susceptibility gene, pRb, acts as a tumor suppressor and loss of its function is involved in the development of various types of cancer. DNA tumor viruses are supposed to disturb the normal regulation of the cell cycle by inactivating pRb. However, a direct function of pRb in regulation of the cell cycle has hitherto not been shown. We demonstrate here that the cell cycle-dependent expression of one of the G1-phase cyclins, cyclin D1, is dependent on the presence of a functional Rb protein. Rb-deficient tumor cell lines as well as cells expressing viral oncoproteins (large tumor antigen of simian virus 40, early region 1A of adenovirus, early region 7 of papillomavirus) have low or barely detectable levels of cyclin D1. Expression of cyclin D1, but not of cyclins A and E, is induced by transfection of the Rb gene into Rb-deficient tumor cells. Cotransfection of a reporter gene under the control of the D1 promoter, together with the Rb gene, into Rb-deficient cell lines demonstrates stimulation of the D1 promoter by Rb, which parallels the stimulation of endogenous cyclin D1 gene expression. Our finding that pRb stimulates expression of a key component of cell cycle control, cyclin D1, suggests the existence of a regulatory loop between pRb and cyclin D1 and extends existing models of tumor suppressor function.

• MeSH
• buněčný cyklus * MeSH
• cyklin D1 MeSH
• cykliny genetika   metabolismus   MeSH
• DNA primery chemie   MeSH
• lidé MeSH
• messenger RNA genetika   MeSH
• molekulární sekvence - údaje MeSH
• nádorové buňky kultivované MeSH
• onkogenní proteiny genetika   metabolismus   MeSH
• promotorové oblasti (genetika) MeSH
• regulace genové exprese MeSH
• retinoblastomový protein * metabolismus   MeSH
• sekvence nukleotidů MeSH
• techniky in vitro MeSH
• Check Tag
• lidé MeSH

One of the most significant insults that jeopardize cardiomyocyte homeostasis is a surge of reactive oxygen species (ROS) in the failing myocardium. Early growth response factor-1 (Egr-1) has been found to act as a transcriptional regulator in multiple biological processes known to exert deleterious effects on cardiomyocytes. We thus investigated the signaling pathways involved in its regulation by H2O2. Egr-1 mRNA levels were found to be maximally induced after 2 h in H2O2-treated H9c2 cells. Egr-1 respective response at the protein level, was found to be maximally induced after 2 h of treatment with 200 µM H2O2, remaining elevated for 6 h, and declining thereafter. H2O2- induced upregulation of Egr-1 mRNA and protein levels was ablated in the presence of agents inhibiting ERKs pathway (PD98059) and JNKs (SP600125, AS601245). Immunofluorescent experiments revealed H2O2-induced Egr-1 nuclear sequestration to be also ERK- and JNK-dependent. Overall, our results show for the first time the fundamental role of ERKs and JNKs in regulating Egr-1 response to H2O2 treatment in cardiac cells at multiple levels: mRNA, protein and subcellular distribution. Nevertheless, further studies are required to elucidate the specific physiological role of Egr-1 regarding the modulation of gene expression and determination of cell fate.

• MeSH
• aktivní transport - buněčné jádro MeSH
• buněčné jádro enzymologie   účinky léků   MeSH
• buněčné linie MeSH
• časové faktory MeSH
• extracelulárním signálem regulované MAP kinasy antagonisté a inhibitory   metabolismus   MeSH
• financování organizované MeSH
• fluorescenční protilátková technika MeSH
• inhibitory proteinkinas farmakologie   MeSH
• JNK mitogenem aktivované proteinkinasy antagonisté a inhibitory   metabolismus   MeSH
• kardiomyocyty enzymologie   účinky léků   MeSH
• krysa rodu rattus MeSH
• messenger RNA metabolismus   MeSH
• peroxid vodíku farmakologie   MeSH
• protein 1 časné růstové odpovědi genetika   metabolismus   MeSH
• upregulace MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH

The essential components of splicing are the splicing factors accumulated in nuclear speckles; thus, we studied how DNA damaging agents and A-type lamin depletion affect the properties of these regions, positive on the SC-35 protein. We observed that inhibitor of PARP (poly (ADP-ribose) polymerase), and more pronouncedly inhibitors of RNA polymerases, caused DNA damage and increased the SC35 protein level. Interestingly, nuclear blebs, induced by PARP inhibitor and observed in A-type lamin-depleted or senescent cells, were positive on both the SC-35 protein and another component of the spliceosome, SRRM2. In the interphase cell nuclei, SC-35 interacted with the phosphorylated form of RNAP II, which was A-type lamin-dependent. In mitotic cells, especially in telophase, the SC35 protein formed a well-visible ring in the cytoplasmic fraction and colocalized with β-catenin, associated with the plasma membrane. The antibody against the SRRM2 protein showed that nuclear speckles are already established in the cytoplasm of the late telophase and at the stage of early cytokinesis. In addition, we observed the occurrence of splicing factors in the nuclear blebs and micronuclei, which are also sites of both transcription and splicing. This conclusion supports the fact that splicing proceeds transcriptionally. According to our data, this process is A-type lamin-dependent. Lamin depletion also reduces the interaction between SC35 and β-catenin in mitotic cells.

• MeSH
• HeLa buňky MeSH
• laminy metabolismus   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• PARP inhibitory terapeutické užití   MeSH
• poly(ADP-ribosa)polymerasa 1 MeSH
• RNA-polymerasa II metabolismus   MeSH
• sestřihové faktory metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Nicotinamide phosphoribosyltransferase (NAMPT) is located in both the nucleus and cytoplasm and has multiple biological functions including catalyzing the rate-limiting step in NAD synthesis. Moreover, up-regulated NAMPT expression has been observed in many cancers. However, the determinants and regulation of NAMPT's nuclear transport are not known. Here, we constructed a GFP-NAMPT fusion protein to study NAMPT's subcellular trafficking. We observed that in unsynchronized 3T3-L1 preadipocytes, 25% of cells had higher GFP-NAMPT fluorescence in the cytoplasm, and 62% had higher GFP-NAMPT fluorescence in the nucleus. In HepG2 hepatocytes, 6% of cells had higher GFP-NAMPT fluorescence in the cytoplasm, and 84% had higher GFP-NAMPT fluorescence in the nucleus. In both 3T3-L1 and HepG2 cells, GFP-NAMPT was excluded from the nucleus immediately after mitosis and migrated back into it as the cell cycle progressed. In HepG2 cells, endogenous, untagged NAMPT displayed similar changes with the cell cycle, and in nonmitotic cells, GFP-NAMPT accumulated in the nucleus. Similarly, genotoxic, oxidative, or dicarbonyl stress also caused nuclear NAMPT localization. These interventions also increased poly(ADP-ribosyl) polymerase and sirtuin activity, suggesting an increased cellular demand for NAD. We identified a nuclear localization signal in NAMPT and amino acid substitution in this sequence (424RSKK to ASGA), which did not affect its enzymatic activity, blocked nuclear NAMPT transport, slowed cell growth, and increased histone H3 acetylation. These results suggest that NAMPT is transported into the nucleus where it presumably increases NAD synthesis required for cell proliferation. We conclude that specific inhibition of NAMPT transport into the nucleus might be a potential avenue for managing cancer.

• MeSH
• akrylamidy farmakologie   MeSH
• aktivní transport - buněčné jádro MeSH
• buněčné jádro metabolismus   MeSH
• buňky 3T3-L1 MeSH
• buňky Hep G2 MeSH
• cytoplazma metabolismus   MeSH
• histony metabolismus   MeSH
• kontrolní body buněčného cyklu MeSH
• lidé MeSH
• mutageneze cílená MeSH
• myši MeSH
• NAD metabolismus   MeSH
• nikotinamidfosforibosyltransferasa chemie   genetika   metabolismus   MeSH
• oxidační stres MeSH
• piperidiny farmakologie   MeSH
• poly(ADP-ribosa)polymerasy metabolismus   MeSH
• proliferace buněk MeSH
• rekombinantní fúzní proteiny chemie   genetika   metabolismus   MeSH
• sirtuiny metabolismus   MeSH
• viabilita buněk účinky léků   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Eukaryotic RNA can carry more than 100 different types of chemical modifications. Early studies have been focused on modifications of highly abundant RNA, such as ribosomal RNA and transfer RNA, but recent technical advances have made it possible to also study messenger RNA (mRNA). Subsequently, mRNA modifications, namely methylation, have emerged as key players in eukaryotic gene expression regulation. The most abundant and widely studied internal mRNA modification is N6 -methyladenosine (m6 A), but the list of mRNA chemical modifications continues to grow as fast as interest in this field. Over the past decade, transcriptome-wide studies combined with advanced biochemistry and the discovery of methylation writers, readers, and erasers revealed roles for mRNA methylation in the regulation of nearly every aspect of the mRNA life cycle and in diverse cellular, developmental, and disease processes. Although large parts of mRNA function are linked to its cytoplasmic stability and regulation of its translation, a number of studies have begun to provide evidence for methylation-regulated nuclear processes. In this review, we summarize the recent advances in RNA methylation research and highlight how these new findings have contributed to our understanding of methylation-dependent RNA processing in the nucleus. This article is categorized under: RNA Processing > RNA Editing and Modification RNA Processing > Splicing Regulation/Alternative Splicing RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.

• MeSH
• buněčné jádro metabolismus   MeSH
• epigeneze genetická MeSH
• lidé MeSH
• messenger RNA metabolismus   MeSH
• metylace MeSH
• prekurzory RNA metabolismus   MeSH
• transkriptom MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

The mammalian D-type cyclins promote progression through a G1 checkpoint by phosphorylating the retinoblastoma protein (pRB), and can contribute to oncogenesis via their deregulated expression achieved through gene amplification, chromosomal rearrangement, or retroviral integration. We now report a novel mechanism of tumour-associated D-cyclin over-abundance, resulting from enhanced protein stability. In two human cell lines established from a single uterine sarcoma biopsy, pRB-positive SK-UT-1B and pRB-deficient SK-UT-1, aberrant accumulation of functional cyclins D1, and D2 and D3 occurred in the absence of gene amplification and/or elevated mRNA expression. The abundance of D-cyclin proteins remained elevated throughout the cell cycle, and pulse-chase experiments revealed six to 10-fold prolongation of their protein half-lives as compared with either diploid fibroblasts or control U-2-OS sarcoma cells. These results point to a critical regulatory role of D-type cyclin turnover, and contribute to refinement of current views of the role played by the cyclin D-CDK-p16-pRB pathway in cell cycle control and tumorigenesis.

• MeSH
• aktivace enzymů MeSH
• amplifikace genu MeSH
• cyklin D MeSH
• cyklin-dependentní kinasa 4 MeSH
• cyklin-dependentní kinasy metabolismus   MeSH
• cykliny genetika   metabolismus   MeSH
• imunoblotting MeSH
• lidé MeSH
• messenger RNA genetika   metabolismus   MeSH
• nádorové buňky kultivované MeSH
• nádorové proteiny genetika   metabolismus   MeSH
• nádory dělohy genetika   metabolismus   MeSH
• protoonkogenní proteiny * MeSH
• retinoblastomový protein genetika   metabolismus   MeSH
• sarkom metabolismus   MeSH
• stabilita léku MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Nuclear locations of the c-myc gene and its transcripts (c-myc (T)) have been investigated in relation to nuclear domains involved in RNA synthesis and processing. Transcription of the c-myc gene appears to be linked to the late G(1)- and preferentially to S-phases of the cell cycle. The c-myc gene and its transcripts were positioned non-randomly within the interphase nucleus; additionally, c-myc RNA signals accumulated at nucleoli. Using oligo-probes, designed to exon II and exon III of the c-myc gene, single c-myc (T) was preferentially observed in human carcinoma HT29 and A549 cells. Conversely, human embryonal teratocarcinoma NTERA cells were characterized by the presence of multiple c-myc RNA signals located in both the nucleoli and nucleoplasm. When accumulated at nucleoli, c-myc (T) occupied the periphery of this organelle, though not those associated with the cultivation surface. In HT29 cells, approximately 80% of c-myc (T) co-localized with the RNAP II positive regions, so-called transcription factories. However, in approximately 20% of the cells with c-myc transcripts, the c-myc (T) was released from the site of synthesis, and was not associated with either transcription factories or SC35 domains. In approximately 60% of nuclei with c-myc (T), these signals were located in close proximity to the SC35 regions, but promyelocytic leukaemia bodies were associated with c-myc (T) only in approximately 20% of the nuclei. Taken together, c-myc RNA signals were positioned in the most internal parts of the cell nuclei preferentially associated with the nucleoli. Specific nuclear and nucleolar positioning probably reflects the kinetics of c-myc RNA metabolism.

• MeSH
• buněčné jádro genetika   metabolismus   ultrastruktura   MeSH
• buňky HT-29 MeSH
• exprese genu MeSH
• financování organizované MeSH
• genetická transkripce MeSH
• geny myc MeSH
• lidé MeSH
• lidské chromozomy, pár 8 MeSH
• messenger RNA metabolismus   MeSH
• nádorové buňky kultivované MeSH
• protoonkogenní proteiny c-myc metabolismus   MeSH
• RNA-polymerasa II metabolismus   MeSH
• tkáňová distribuce MeSH
• Check Tag
• lidé MeSH

Although it is well known that chromosomes are non-randomly organized during interphase, it is not completely clear whether higher-order chromatin structure is transmitted from mother to daughter cells. Therefore, we addressed the question of how chromatin is rearranged during interphase and whether heterochromatin pattern is transmitted after mitosis. We additionally tested the similarity of chromatin arrangement in sister interphase nuclei. We noticed a very active cell rotation during interphase, especially when histone hyperacetylation was induced or transcription was inhibited. This natural phenomenon can influence the analysis of nuclear arrangement. Using photoconversion of Dendra2-tagged core histone H4 we showed that the distribution of chromatin in daughter interphase nuclei differed from that in mother cells. Similarly, the nuclear distribution of heterochromatin protein 1β (HP1β) was not completely identical in mother and daughter cells. However, identity between mother and daughter cells was in many cases evidenced by nucleolar composition. Moreover, morphology of nucleoli, HP1β protein, Cajal bodies, chromosome territories, and gene transcripts were identical in sister cell nuclei. We conclude that the arrangement of interphase chromatin is not transmitted through mitosis, but the nuclear pattern is identical in naturally synchronized sister cells. It is also necessary to take into account the possibility that cell rotation and the degree of chromatin condensation during functionally specific cell cycle phases might influence our view of nuclear architecture.

• MeSH
• buněčné jadérko účinky léků   genetika   ultrastruktura   MeSH
• buněčné linie MeSH
• Cajalova tělíska účinky léků   genetika   ultrastruktura   MeSH
• chromozomální proteiny, nehistonové genetika   metabolismus   MeSH
• daktinomycin farmakologie   MeSH
• fluorescenční barviva MeSH
• fluorescenční mikroskopie MeSH
• fotochemické procesy MeSH
• heterochromatin účinky léků   genetika   ultrastruktura   MeSH
• histony genetika   metabolismus   MeSH
• inhibitory histondeacetylas farmakologie   MeSH
• inhibitory syntézy proteinů farmakologie   MeSH
• interfáze účinky léků   genetika   MeSH
• kyseliny hydroxamové farmakologie   MeSH
• lidé MeSH
• messenger RNA biosyntéza   MeSH
• mitóza účinky léků   genetika   MeSH
• myši MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• buněčné jádro genetika   metabolismus   MeSH
• jaderné proteiny metabolismus   MeSH
• kompartmentace buňky MeSH
• lidé MeSH
• messenger RNA metabolismus   MeSH
• prekurzory RNA MeSH
• Check Tag
• lidé MeSH