Our previous studies have shown that the 3′ end of metastasis associated lung adenocarcinoma transcript 1 (MALAT1) is involved in colorectal cancer (CRC) cell proliferation and migration/invasion in ...vitro. The role and mechanism of MALAT1 in CRC metastasis in vivo, however, remain largely unknown. In the present study, we found that MALAT1 was up-regulated in human primary CRC tissues with lymph node metastasis. Overexpression of MALAT1 via RNA activation promoted CRC cell proliferation, invasion and migration in vitro, and stimulated tumor growth and metastasis in mice in vivo. Conversely, knockdown of MALAT1 inhibited CRC tumor growth and metastasis. MALAT1 regulated at least 243 genes in CRC cells in a genome-wide expression profiling. Among these genes, PRKA kinase anchor protein 9 (AKAP-9) was significantly up-regulated at both mRNA and protein levels. AKAP-9 was highly expressed in CRC cells with metastatic potential and human primary CRC tissues with lymph node metastasis, but not in normal cells or tissues. Importantly, knockdown of AKAP-9 blocked MALAT1-mediated CRC cell proliferation, migration and invasion. These data indicate that MALAT1 may promote CRC tumor development via its target protein AKAP-9.
•MALAT1 is up-regulated in human primary CRC tissues with lymph node metastasis.•MALAT1 can be induced via RNA activation.•MALAT1 plays a critical role in CRC tumor growth and metastasis in mice.•AKAP-9 is correlated with MALAT1 in CRC tissues.•AKAP-9 mediates MALAT1 function in CRC proliferation/migration/invasion.
Animal cells have a remarkable capacity to adopt durable and heritable gene expression programs or epigenetic states that define the physical properties and diversity of somatic cell types. The ...maintenance of epigenetic programs depends on poorly understood pathways that prevent gain or loss of inherited signals. In the germline, epigenetic factors are enriched in liquid-like perinuclear condensates called nuage. Here, we identify the deeply conserved helicase-domain protein, ZNFX-1, as an epigenetic regulator and component of nuage that interacts with Argonaute systems to balance epigenetic inheritance. Our findings suggest that ZNFX-1 promotes the 3′ recruitment of machinery that propagates the small RNA epigenetic signal and thus counteracts a tendency for Argonaute targeting to shift 5′ along the mRNA. These functional insights support the idea that recently identified subdomains of nuage, including ZNFX-1 granules or “Z-granules,” may define spatial and temporal zones of molecular activity during epigenetic regulation.
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•Genetic identification of ZNFX-1, a conserved epigenetic inheritance factor•ZNFX-1 balances the transgenerational inheritance of epigenetic information•ZNFX-1 interacts with RdRP and three distinct Argonaute systems in germline nuage•ZNFX-1 promotes balanced amplification of small RNA signals along germline mRNAs
Ishidate et al. identify ZNFX-1, a highly conserved helicase protein, as a factor required for epigenetic inheritance in C. elegans. Their findings indicate that ZNFX-1 localizes within nuage, where it interacts with Argonaute systems and RNA-dependent RNA polymerase (RdRP) to ensure balanced amplification of small RNA signals along germline mRNAs.
Small activating RNAs （saRNAs） targeting specific promoter regions are able to stimulate gene expression at the transcriptional level, a phenomenon known as RNA activation （RNAa）. It is known that ...RNAa depends on Ago2 and is associated with epigenetic changes at the target promoters. However, the precise molecular mechanism of RNAa remains elusive. Using human CDKN1A （p21） as a model gene, we characterized the molecular nature of RNAa. We show that saRNAs guide Ago2 to and associate with target promoters, saRNA-loaded Ago2 facilitates the assembly of an RNA-induced transcriptional activation （RITA） complex, which, in addition to saRNA-Ago2 complex, includes RHA and CTR9, the latter being a component of the PAFI complex. RITA interacts with RNA polymerase II to stimulate transcription initiation and productive elongation, accompanied by monoubiquitination of histone 2B. Our results establish the existence of a cellular RNA-guided genome-targeting and transcriptional activation mechanism and provide important new mechanistic insights into the RNAa process.
Recent studies have reported that chemically synthesized double-stranded RNAs (dsRNAs), also known as small activating RNA (saRNAs), can specifically induce gene expression by targeting promoter ...sequences by a mechanism termed RNA activation (RNAa). In the present study, we designed 4 candidate saRNAs targeting the Von Hippel-Lindau (VHL) gene promoter. Among these saRNAs, dsVHL-821 significantly inhibited cell growth by up-regulating VHL at both the mRNA and protein levels in renal cell carcinoma 769-P cells. Functional analysis showed that dsVHL-821 induced apoptosis by increasing p53, decreasing Bcl-xL, activating caspase 3/7 and poly-ADP-ribose polymerase in a dose-dependent manner. Chromatin immunoprecipitation analysis revealed that dsVHL-821 increased the enrichment of Ago2 and RNA polymerase II at the dsVHL-821 target site. In addition, Ago2 depletion significantly suppressed dsVHL-821-induced up-regulation of VHL gene expression and related effects. Single transfection of dsVHL-821 caused long-lasting (14 days) VHL up-regulation. Furthermore, the activation of VHL by dsVHL-821 was accompanied by an increase in dimethylation of histone 3 at lysine 4 (H3K4me2) and acetylation of histone 4 (H4ac) and a decrease in dimethylation of histone 3 at lysine 9 (H3K9me2) and lysine 27 (H3K27me2) in the dsVHL-821 target region. Taken together, these results demonstrate that dsVHL-821, a novel saRNA for VHL, induces the expression of the VHL gene by epigenetic changes, leading to inhibition of cell growth and induction of apoptosis, and suggest that targeted activation of VHL by dsVHL-821 may be explored as a novel treatment of renal cell carcinoma.
RNA interference (RNAi) is an important phenomenon that has diverse genetic regulatory functions at the pre- and posttranscriptional levels. The major trigger for the RNAi pathway is double-stranded ...RNA (dsRNA). dsRNA is processed to generate various types of major small noncoding RNAs (ncRNAs) that include microRNAs (miRNAs), small interfering RNAs (siRNAs) and PIWI-interacting RNAs (piRNAs) in Drosophila melanogaster (D. melanogaster). Functionally, these small ncRNAs play critical roles in virtually all biological systems and developmental pathways. Identification and processing of dsRNAs and activation of RNAi machinery are the three major academic interests that surround RNAi research. Mechanistically, some of the important biological functions of RNAi are achieved through: (i) supporting genomic stability via degradation of foreign viral genomes; (ii) suppressing the movement of transposable elements and, most importantly, (iii) post-transcriptional regulation of gene expression by miRNAs that contribute to regulation of epigenetic modifications such as heterochromatin formation and genome imprinting. Here, we review various routes of small ncRNA biogenesis, as well as different RNAi-mediated pathways in D. melanogaster with a particular focus on signaling pathways. In addition, a critical discussion of the most relevant and latest findings that concern the significant contribution of small ncRNAs to the regulation of D. melanogaster physiology and pathophysiology is presented.
Recent studies have reported that small double-strand RNAs (dsRNAs) can activate endogenous genes via an RNA-based promoter targeting mechanism termed RNA activation (RNAa). In the present study, we ...showed that dsVDUP1-834, a novel small activating RNA (saRNA) targeting promoter of vitamin D3 up-regulated protein 1 (VDUP1) gene, up-regulated expression of VDUP1 at both mRNA and protein levels in A549 lung cancer cells. We also demonstrated that dsVDUP1-834 inhibited cell proliferation in A549 lung cancer cells. Further studies showed that dsVDUP1-834 induced cell-cycle arrest by increasing p27 and p53 and decreasing cyclin A and cyclin B1. In addition, knockdown of VDUP1 abrogated dsVDUP1-834-induced up-regulation of VDUP1 gene expression and related effects. The activation of VDUP1 by dsVDUP1-834 was accompanied by an increase in dimethylation of histone 3 at lysine 4 (H3K4me2) and acetylation of histone 3 (H3ac) and a decrease in dimethylation of histone 3 at lysine 9 (H3K9me2) at the target site of VDUP1 promoter. Moreover, the enrichment of Ago2 was detected at the dsVDUP1-834 target site, and Ago2 knockdown significantly suppressed dsVDUP1-834-mediated inhibition of cell proliferation and modulation of cell-cycle regulators. Taken together, the results presented in this report demonstrate that dsVDUP1-834 induces VDUP1 gene expression by epigenetic changes, resulting in cell growth inhibition and cell-cycle arrest. Our results suggest that targeted induction of VDUP1 by dsVDUP1-834 might be a promising therapeutic strategy for the treatment of lung cancer.
Selenium (Se) has been a focus of attention as an important micronutrient with its impact on human health, with there being consequences either due to excess or deficiency in intake. Radiochemical ...neutron activation analysis (RNAA) is well established method for determination of a number of elements at trace level concentrations with high sensitivities. In this work, we used the RNAA method for determination of selenium content in
L. The result of this study was compared with those samples from India and Serbia. The result obtained show that, Se concentration obtained in
L., is close to the minimal FAO recommendation.
In Algeria, Data and studies on the non-metal trace element selenium (Se) are presently lacking, therefore, the aim of this investigation is to provide new data on (Se) element via its determination ...for the first time from Mentha pulegium L. plant. The plant samples were collected in summer of 2012 from Ain-Oussera region, Djelfa province, Algeria; they were dried and powdered. After the neutron irradiation, the samples were digested using high oxidative reagents including H2SO4, HNO3, H2O2 and HCl. The end of this process gave two phases, organic and aqueous discard phase. By using a separating funnel, the organic phase was transferred into a vial in order to measure their induce radionuclide 75Se using gamma-ray spectrometer. A non-chromatographic and sensitive analytical technique RNAA (Radiochemical Neutron Activation Analysis), was applied in this investigation due to its great significant minor systematic error. Results were determined using two distinguish calculation methods, relative-RNAA and k0-RNAA, the findings were quite significant, whereas, the average separation yield was about 85% for both calculation methodologies. Moreover, (Se) concentration obtained from M. pulegium L., is close to the minimal FAO (Food and Agriculture Organization of the United Nations) recommended consumption.
•A non-chromatographic Radiochemical Neutron Activation Analysis was achieved for the separation of selenium.•The average separation yield was ranging between 84% and 87% for both calculation methods.•The trace element selenium has attracted attention because of its impact on human health.•The mean concentration obtained from M. pulegium L. leaves, is close to the minimal FAO recommendation.
RNA-mediated gene activation Jiao, Alan L; Slack, Frank J
Epigenetics,
01/2014, Letnik:
9, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The regulation of gene expression by non-coding RNAs (ncRNAs) has become a new paradigm in biology. RNA-mediated gene silencing pathways have been studied extensively, revealing diverse epigenetic ...and posttranscriptional mechanisms. In contrast, the roles of ncRNAs in activating gene expression remains poorly understood. In this review, we summarize the current knowledge of gene activation by small RNAs, long non-coding RNAs, and enhancer-derived RNAs, with an emphasis on epigenetic mechanisms.
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