BACKGROUND: Polycomb repressive complexes 1 and 2 play important roles in epigenetic gene regulation by posttranslationally modifying specific histone residues. Polycomb repressive complex 2 is responsible for the trimethylation of lysine 27 on histone H3; Polycomb repressive complex 1 catalyzes the monoubiquitination of histone H2A at lysine 119. Both complexes have been thoroughly studied in Arabidopsis, but the evolution of polycomb group gene families in monocots, particularly those with complex allopolyploid origins, is unknown. RESULTS: Here, we present the in silico identification of the Polycomb repressive complex 1 and 2 (PRC2, PRC1) subunits in allohexaploid bread wheat, the reconstruction of their evolutionary history and a transcriptional analysis over a series of 33 developmental stages. We identified four main subunits of PRC2 [E(z), Su(z), FIE and MSI] and three main subunits of PRC1 (Pc, Psc and Sce) and determined their chromosomal locations. We found that most of the genes coding for subunit proteins are present as paralogs in bread wheat. Using bread wheat RNA-seq data from different tissues and developmental stages throughout plant ontogenesis revealed variable transcriptional activity for individual paralogs. Phylogenetic analysis showed a high level of protein conservation among temperate cereals. CONCLUSIONS: The identification and chromosomal location of the Polycomb repressive complex 1 and 2 core components in bread wheat may enable a deeper understanding of developmental processes, including vernalization, in commonly grown winter wheat.

• Klíčová slova
• Epigenetics, Histone methylation, PRC2, Polycomb repressive complex, Wheat,
• MeSH
• chromozomy rostlin MeSH
• fylogeneze MeSH
• mapování chromozomů MeSH
• molekulární evoluce MeSH
• počítačová simulace MeSH
• PRC1 genetika   MeSH
• PRC2 genetika   MeSH
• pšenice genetika   MeSH
• RNA rostlin MeSH
• sekvenování transkriptomu MeSH
• stanovení celkové genové exprese MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• PRC1 MeSH
• PRC2 MeSH
• RNA rostlin MeSH

Lung cancer is the most common cause of cancer deaths. The expression of the transcription factor C/EBPα (CCAAT/enhancer binding protein α) is frequently lost in non-small cell lung cancer, but the mechanisms by which C/EBPα suppresses tumor formation are not fully understood. In addition, no pharmacological therapy is available to specifically target C/EBPα expression. We discovered a subset of pulmonary adenocarcinoma patients in whom negative/low C/EBPα expression and positive expression of the oncogenic protein BMI1 (B lymphoma Mo-MLV insertion region 1 homolog) have prognostic value. We also generated a lung-specific mouse model of C/EBPα deletion that develops lung adenocarcinomas, which are prevented by Bmi1 haploinsufficiency. BMI1 activity is required for both tumor initiation and maintenance in the C/EBPα-null background, and pharmacological inhibition of BMI1 exhibits antitumor effects in both murine and human adenocarcinoma lines. Overall, we show that C/EBPα is a tumor suppressor in lung cancer and that BMI1 is required for the oncogenic process downstream of C/EBPα loss. Therefore, anti-BMI1 pharmacological inhibition may offer a therapeutic benefit for lung cancer patients with low expression of C/EBPα and high BMI1.

• MeSH
• adenokarcinom plic MeSH
• adenokarcinom genetika   metabolismus   patologie   terapie   MeSH
• lidé MeSH
• mutace genetika   MeSH
• myši knockoutované MeSH
• myši MeSH
• nádory plic genetika   metabolismus   patologie   terapie   MeSH
• PRC1 genetika   metabolismus   MeSH
• protein alfa vázající zesilovač transkripce CCAAT genetika   metabolismus   MeSH
• protoonkogenní proteiny genetika   metabolismus   MeSH
• regulace genové exprese u nádorů genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• BMI1 protein, human MeSH Prohlížeč
• Bmi1 protein, mouse MeSH Prohlížeč
• PRC1 MeSH
• protein alfa vázající zesilovač transkripce CCAAT MeSH
• protoonkogenní proteiny MeSH

BACKGROUND INFORMATION: The optimal repair of DNA lesions is fundamental for physiological processes. We asked whether the recruitment of HP1β, 53BP1 and BMI1 proteins to ultraviolet (UVA)-induced DNA lesions requires functional A-type lamins. RESULTS: We found that UVA irradiation of nuclear lamina abolished the fluorescence of mCherry-tagged A-type lamins and destroyed the nuclear lamina as also observed by electron microscopy studies. Similarly, an absence of endogenous A- and B-type lamins was found in irradiated regions by UVA. However, irradiation did not affect the recruitment of HP1β, 53BP1 and BMI1 to DNA lesions. The UVA-induced shrinkage of the nuclear lamina, which anchors chromatin, explains why UVA-micro-irradiated chromatin is relaxed. Conversely, additional experiments with γ-irradiation showed that the nuclear lamina remained intact and the genome-wide level of HP1β was stable. Fluorescence intensity of HP1β and BMI1 in UVA-induced DNA lesions and level of HP1β after γ-irradiation were unaffected by deficiency in A-type lamins, whereas those parameters of 53BP1 were changed. CONCLUSIONS: We conclude that only the 53BP1 status in DNA lesions, induced by UVA or γ-rays, is affected by A-type lamin deficiency, which was not observed for heterochromatin-related proteins HP1β and BMI1.

• Klíčová slova
• Chromatin, DNA damage, HP1, Lamins, Protein mobility,
• MeSH
• 53BP1 MeSH
• buňky 3T3 MeSH
• chromozomální proteiny, nehistonové analýza   metabolismus   MeSH
• DNA vazebné proteiny analýza   metabolismus   MeSH
• DNA genetika   MeSH
• lamin typ A analýza   metabolismus   MeSH
• myši MeSH
• poškození DNA účinky záření   MeSH
• PRC1 analýza   metabolismus   MeSH
• protoonkogenní proteiny analýza   metabolismus   MeSH
• ultrafialové záření MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 53BP1 MeSH
• Bmi1 protein, mouse MeSH Prohlížeč
• Cbx1 protein, mouse MeSH Prohlížeč
• chromozomální proteiny, nehistonové MeSH
• DNA vazebné proteiny MeSH
• DNA MeSH
• lamin typ A MeSH
• PRC1 MeSH
• protoonkogenní proteiny MeSH
• Trp53bp1 protein, mouse MeSH Prohlížeč

BACKGROUND INFORMATION: A Polycomb (PcG) body is an orphan nuclear subcompartment characterised by accumulations of Polycomb repressive complex 1 (PRC1) proteins. However, seemingly contradictory reports have appeared that describe the PcG bodies either as protein-based bodies in the interchromatin compartment or chromatin domains. In this respect, molecular crowding is an important factor for the assembly and stability of nuclear subcompartments. In order to settle this contradiction, crowding experiments, that represent a convenient model distinguishing between interchromatin and chromatin compartments, were carried out. RESULTS: In sucrose-hypertonically induced crowding, we observed in U-2 OS cells that PcG bodies disappeared, but persisted as nuclear domains characterised by accumulations of DNA. This phenomenon was also observed in cells hypertonically treated with sorbitol and NaCl. Importantly, the observed changes were quickly reversible after re-incubation of cells in normal medium. We found that the PcG foci disappearance and the dissociation of PRC1 proteins (BMI1 and RING1a proteins) from chromatin were associated with their hyper-phosphorylation. In addition, under hyper- and hypotonic conditions, the behaviour of the PcG bodies differed from that of the typical nucleoplasmic body. CONCLUSION: PRC1 proteins accumulations do not represent a genuine nuclear subcompartment. The PcG body is a chromosomal domain, rather than a nucleoplasmic body.

• Klíčová slova
• Molecular crowding, Nuclear subcompartments, Polycomb body, Polycomb group proteins, Post-translational chromatin modifications,
• MeSH
• anthrachinony metabolismus   MeSH
• barvení a značení MeSH
• chromatin metabolismus   MeSH
• fluorescence MeSH
• fosforylace účinky léků   MeSH
• genetická transkripce účinky léků   MeSH
• hypertonické roztoky farmakologie   MeSH
• lidé MeSH
• makromolekulární látky metabolismus   MeSH
• nádorové buněčné linie MeSH
• polycomb proteiny metabolismus   MeSH
• PRC1 metabolismus   MeSH
• RNA genetika   metabolismus   MeSH
• sacharosa farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1,5-bis((2-(methylamino)ethyl)amino)-4,8-dihydroxyanthracene-9,10-dione MeSH Prohlížeč
• anthrachinony MeSH
• BMI1 protein, human MeSH Prohlížeč
• chromatin MeSH
• hypertonické roztoky MeSH
• makromolekulární látky MeSH
• polycomb proteiny MeSH
• PRC1 MeSH
• RING1 protein, human MeSH Prohlížeč
• RNA MeSH
• sacharosa MeSH

Polycomb group (PcG) proteins, organized into Polycomb bodies, are important regulatory components of epigenetic processes involved in the heritable transcriptional repression of target genes. Here, we asked whether acetylation can influence the nuclear arrangement and function of the BMI1 protein, a core component of the Polycomb group complex, PRC1. We used time-lapse confocal microscopy, micro-irradiation by UV laser (355 nm) and GFP technology to study the dynamics and function of the BMI1 protein. We observed that BMI1 was recruited to UV-damaged chromatin simultaneously with decreased lysine acetylation, followed by the recruitment of heterochromatin protein HP1β to micro-irradiated regions. Pronounced recruitment of BMI1 was rapid, with half-time τ = 15 sec; thus, BMI1 is likely involved in the initiation step leading to the recognition of UV-damaged sites. Histone hyperacetylation, stimulated by HDAC inhibitor TSA, suppression of transcription by actinomycin D, and ATP-depletion prevented increased accumulation of BMI1 to γH2AX-positive irradiated chromatin. Moreover, BMI1 had slight ability to recognize spontaneously occurring DNA breaks caused by other pathophysiological processes. Taken together, our data indicate that the dynamics of recognition of UV-damaged chromatin, and the nuclear arrangement of BMI1 protein can be influenced by acetylation and occur as an early event prior to the recruitment of HPβ to UV-irradiated chromatin.

• MeSH
• acetylace MeSH
• buněčné linie MeSH
• buňky 3T3 MeSH
• časosběrné zobrazování MeSH
• chromatin metabolismus   účinky záření   MeSH
• chromozomální proteiny, nehistonové genetika   metabolismus   MeSH
• FRAP MeSH
• histony metabolismus   MeSH
• homolog proteinu s chromoboxem 5 MeSH
• inhibitory histondeacetylas metabolismus   MeSH
• jaderné proteiny genetika   metabolismus   MeSH
• konfokální mikroskopie metody   MeSH
• kyseliny hydroxamové metabolismus   MeSH
• lidé MeSH
• myši MeSH
• polycomb proteiny MeSH
• poškození DNA MeSH
• PRC1 MeSH
• protoonkogenní proteiny genetika   metabolismus   MeSH
• rekombinantní fúzní proteiny genetika   metabolismus   MeSH
• represorové proteiny genetika   metabolismus   MeSH
• ultrafialové záření MeSH
• zelené fluorescenční proteiny genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• BMI1 protein, human MeSH Prohlížeč
• CBX1 protein, human MeSH Prohlížeč
• chromatin MeSH
• chromozomální proteiny, nehistonové MeSH
• histony MeSH
• homolog proteinu s chromoboxem 5 MeSH
• inhibitory histondeacetylas MeSH
• jaderné proteiny MeSH
• kyseliny hydroxamové MeSH
• polycomb proteiny MeSH
• PRC1 MeSH
• protoonkogenní proteiny MeSH
• rekombinantní fúzní proteiny MeSH
• represorové proteiny MeSH
• trichostatin A MeSH Prohlížeč
• zelené fluorescenční proteiny MeSH

PURPOSE: Bmi-1 is a Polycomb group member which participates in many physiological processes as well as in a wide spectrum of cancers. The aim of this study was to investigate Bmi-1 expression in non-small cell lung cancer (NSCLC) in respect to clinicopathological features and therapeutic outcomes. METHODS: Immunohistochemical staining for Bmi-1 was performed on tissue microarrays (TMAs) constructed from 179 formalin-fixed and paraffin-embedded NSCLC samples (106 squamous, 58 adeno-, and 15 large cell carcinomas). Data were subject to statistical analysis by SPSS. RESULTS: Overall evaluation of all tumor cases showed that 20 (11.43%) were negative, 37 (21.14%) showed weak, 65 (37.14%) moderate and 57 (32.57%) strong nuclear positivity for Bmi-1. Statistical analysis of our data revealed that the expression of Bmi-1 was significantly higher in stage III (P = 10(-6)) and stage IV (P = 10(-5)) tumors compared to stages I and II tumors. The administration of adjuvant chemotherapy significantly increased DFS at stage I and II patients who did not express Bmi-1 when compared to their Bmi-1 positive counterparts (P = 0.05). CONCLUSIONS: Our results suggest that Bmi-1 is significantly associated with progression of NSCLC and might serve as a prognostic marker of adverse disease outcome.

• MeSH
• čipová analýza proteinů MeSH
• čipová analýza tkání MeSH
• imunohistochemie MeSH
• jaderné proteiny genetika   metabolismus   MeSH
• lidé MeSH
• nádory plic metabolismus   patologie   MeSH
• nemalobuněčný karcinom plic metabolismus   patologie   MeSH
• PRC1 MeSH
• prognóza MeSH
• protoonkogenní proteiny genetika   metabolismus   MeSH
• represorové proteiny genetika   metabolismus   MeSH
• staging nádorů MeSH
• stanovení celkové genové exprese MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• BMI1 protein, human MeSH Prohlížeč
• jaderné proteiny MeSH
• PRC1 MeSH
• protoonkogenní proteiny MeSH
• represorové proteiny MeSH

It has been demonstrated that over-expression of Bmi-1 occurs in a variety of cancers, including several types of leukemia. This gene plays a key role in the self-renewal of stem cells. Leukemic cells lacking Bmi-1 underwent proliferation arrest and showed signs of differentiation and apoptosis. These findings led to the proposal of Bmi-1 as a potential target for therapeutic intervention in cancer. In this study, we investigated the role of Bmi-1 in chronic myeloid leukemia (CML). Using qRT-PCR, we demonstrated a significantly increased level of Bmi-1 transcript in CML cells. Using array analysis, we determined the deregulation of several genes after Bmi-1 silencing. Proapoptotic genes BAD and TRADD, and CASP8, p16-INK4, BRCA2, Notch4 and Wnt-8B were elevated. PLK1, SOD1, E2F-3, two retinoblastoma binding proteins (RBQ1 and RBBP4) and HDGF were reduced after Bmi-1 inhibition. Additionally, we tested the impact of Bmi-1 siRNA on CML cell growth; however, there was no apparent change after Bmi-1 suppression. Despite the fact that Bmi-1 deregulation occurs in CML and its expression is connected to several oncogenic processes, Bmi-1 seems to play a secondary role in CML transformation.

• MeSH
• buňky K562 MeSH
• chronická myeloidní leukemie genetika   metabolismus   MeSH
• dospělí MeSH
• jaderné proteiny biosyntéza   MeSH
• lidé středního věku MeSH
• lidé MeSH
• malá interferující RNA metabolismus   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• PRC1 MeSH
• proliferace buněk MeSH
• protoonkogenní proteiny biosyntéza   MeSH
• regulace genové exprese u leukemie * MeSH
• represorové proteiny biosyntéza   MeSH
• stanovení celkové genové exprese MeSH
• umlčování genů MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• BMI1 protein, human MeSH Prohlížeč
• jaderné proteiny MeSH
• malá interferující RNA MeSH
• PRC1 MeSH
• protoonkogenní proteiny MeSH
• represorové proteiny MeSH