Natural circular RNA encodes regulatory small peptides in Mammalian cells
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ABSTRACT: To test the hypothesis that circRNAs might encode functional peptides in mammalian cells, we studied the long intergenic non-protein coding RNA, p53 induced transcript (LINC-PINT), which was previously reported as a tumor suppressor and connected p53 activation with polycomb repressive complex 2 (PRC2). We selected this long noncoding RNA (lncRNA) for further analysis because LINC-PINT has a long exon 2 which in accordance with the bioinformatical analyzed circular RNA standard.The following immunoblotting showed 87aa peptide level also decreased, indicating that this peptide is encoded by circPINTexon2. We name this circRNA encoded peptide PINT87aa. To investigate the possible regulatory role of PINT87aa, we did the expression micro array in PINT87aa stably transfect U251 or U87 glioblastoma cells and their control cells. The array analysis reveals that PINT87aa may involve in the cell cycle regulation, anti-apoptosis effects and multiple oncogenic signaling pathway activation.
Project description:To test the hypothesis that circRNAs might encode functional peptides in mammalian cells, we studied the long intergenic non-protein coding RNA, p53 induced transcript (LINC-PINT), which was previously reported as a tumor suppressor and connected p53 activation with polycomb repressive complex 2 (PRC2). We selected this long noncoding RNA (lncRNA) for further analysis because LINC-PINT has a long exon 2 which in accordance with the bioinformatical analyzed circular RNA standard.The following immunoblotting showed 87aa peptide level also decreased, indicating that this peptide is encoded by circPINTexon2. We name this circRNA encoded peptide PINT87aa.
Project description:The aim of this experiment has been to investigate the transcriptional profile of HCT116 cells treated with Peptide-3 (Pep3) compared to untreated (NT), treated with solvent (DMSO) or with a mutated peptide (Pep3M) cells. Peptide-3 is a dodecapeptide able to interact with MDM2 at the levels of the interaction region of the MDM4 and MDM2 proteins, thereby interfering with the coopeartivy function of the proteins in the regulation of p53. This peptide is indeed able to specifically activate p53 and to cause apoptotis in different cancer cell lines and tumor growth inhibition in xenograft models. Three different experimental conditions have been analysed compared to untreated cells at time 0 (NT cells, the starting point of the treatment): cells treated with DMSO solvent (DMSO); treated with peptide-3 (Pep3) and with control peptide (Pep3M). The analysis has been performed at 24 and 48 hours after treatment. In addition, untreated cells after 24 hours of growth have been analysed as further control. All analyses have been performed in triplicates.
Project description:Long noncoding RNAs regulating diverse cellular processes implicate in many diseases. Here, we report the identification of a novel long intergenic noncoding RNA, Linc-ASEN, expressed in prematurely senescent cells, that associates with UPF1 and represses cellular senescence by reducing p21 production transcriptionally and post-transcriptionally. The Linc-ASEN-UPF1 complex suppressed p21 transcription by recruiting Polycomb Repressive Complex 1 (PRC1) and PRC2 to the p21 locus, and thereby preventing binding of the transcriptional activator p53 on the p21 promoter. Moreover, the Linc-ASEN-UPF1 complex repressed p21 expression post-transcriptionally by lowering p21 mRNA stability in association with DCP1A. Accordingly, Linc-ASEN levels were found inversely correlated with p21 mRNA levels in tumor tissues from patient-derived xenograft mice, in various human cancer tissues, and in aged mice tissues. Our studies reveal that Linc-ASEN prevents cellular senescence by reducing the transcription and stability of p21 mRNA in concert with UPF1, and suggest that Linc-ASEN might be a potential therapeutic target in processes influenced by senescence, including cancer.
Project description:Long noncoding RNAs regulating diverse cellular processes implicate in many diseases. Here, we report the identification of a novel long intergenic noncoding RNA, Linc-ASEN, expressed in prematurely senescent cells, that associates with UPF1 and represses cellular senescence by reducing p21 production transcriptionally and post-transcriptionally. The Linc-ASEN-UPF1 complex suppressed p21 transcription by recruiting Polycomb Repressive Complex 1 (PRC1) and PRC2 to the p21 locus, and thereby preventing binding of the transcriptional activator p53 on the p21 promoter. Moreover, the Linc-ASEN-UPF1 complex repressed p21 expression post-transcriptionally by lowering p21 mRNA stability in association with DCP1A. Accordingly, Linc-ASEN levels were found inversely correlated with p21 mRNA levels in tumor tissues from patient-derived xenograft mice, in various human cancer tissues, and in aged mice tissues. Our studies reveal that Linc-ASEN prevents cellular senescence by reducing the transcription and stability of p21 mRNA in concert with UPF1, and suggest that Linc-ASEN might be a potential therapeutic target in processes influenced by senescence, including cancer.
Project description:Long noncoding RNAs regulating diverse cellular processes implicate in many diseases. Here, we report the identification of a novel long intergenic noncoding RNA, Linc-ASEN, expressed in prematurely senescent cells, that associates with UPF1 and represses cellular senescence by reducing p21 production transcriptionally and post-transcriptionally. The Linc-ASEN-UPF1 complex suppressed p21 transcription by recruiting Polycomb Repressive Complex 1 (PRC1) and PRC2 to the p21 locus, and thereby preventing binding of the transcriptional activator p53 on the p21 promoter. Moreover, the Linc-ASEN-UPF1 complex repressed p21 expression post-transcriptionally by lowering p21 mRNA stability in association with DCP1A. Accordingly, Linc-ASEN levels were found inversely correlated with p21 mRNA levels in tumor tissues from patient-derived xenograft mice, in various human cancer tissues, and in aged mice tissues. Our studies reveal that Linc-ASEN prevents cellular senescence by reducing the transcription and stability of p21 mRNA in concert with UPF1, and suggest that Linc-ASEN might be a potential therapeutic target in processes influenced by senescence, including cancer.
Project description:Thousands of long intergenic noncoding RNAs (lincRNAs) are encoded by the mammalian genome, which were reported to have multiple biological functions as transcriptional activators acting in cis 1 or trans 2, transcriptional repressors 3,4 or miRNAs decoys 5,6. However, the function of most lincRNAs has not yet been identified in vivo. Here, we demonstrate a role for linc-MYH, a novel long intergenic noncoding RNA, in adult fast-type myofibre specialization. Skeletal myofibre fast and slow phenotypes are established through differential expression of numerous fibre-specific genes7. We show linc-MYH and the fast MYH genes share a common enhancer located in the fast MYH genes locus and regulated by the Six1 homeoproteins. Muscle-specific Six1 mutant mice show increased expression of slow-type genes, and downregulation of linc-MYH and fast-type genes. linc-MYH function revealed by in vivo knockdown and wide transcriptomic analysis, is in fine to prevent expression of genes ensuring slow muscle contractile properties, and to increase fast-type muscle gene expression in fast-type myofibres. Thus, formation of efficient fast sarcomeric units and appropriate Ca++ cycling and excitation/contraction/relaxation coupling in fast- myofibres is achieved through the coordiante control of fast MYHs and linc-MYH expression by a Six bound enhancer.
Project description:It is now obvious that the majority of cellular transcripts do not code for proteins, and a significant subset of them are long noncoding RNAs (lncRNAs). Many lncRNAs show aberrant expression in cancer, and some of them have been linked to cellular transformation. However, the underlying mechanisms remain poorly understood. Here we characterize the function of the p53-regulated human lncRNA LINC-PINT in cancer. We found that LINC-PINT acts as tumor suppressor lncRNA. Its expression is downregulated in multiple types of cancer and correlates with good prognosis in lung adenocarcinoma. LINC-PINT inhibits the migration capacity and invasive phenotype of cancer cells in vitro and in vivo, and it does so by repressing a proinvasion gene signature in a PRC2-dependent manner. By applying cross-species conservation analysis combined with functional experimental validations we found that the function of LINC-PINT is highly dependent on a short sequence conserved across mammals, sequence that mediates the interaction with PRC2. We propose that LINC-PINT may function as a molecular exchanger that provides PRC2 to active gene promoters for their silencing, mechanisms that could be shared by other PRC2-interacting lncRNAs.
Project description:Long noncoding RNAs (lncRNAs) have emerged as an important layer of genome regulation with common mechanistic themes including the formation of ribonucleoprotein complexes. Here, we present a novel X-linked lncRNA termed linc-Firre that escapes X-chromosome inactivation and forms trans-chromosomal interactions required for adipogenesis. Linc-Firre is exclusively nuclear and forms punctate expression foci on chromatin near its site of transcription on both X-chromosomes in human and mouse. Both the localization of linc-Firre and the association with the nuclear matrix protein hnRNPU require a conserved repeating RNA domain, R2D2. Collectively, these results reveal a lincRNA that escapes X-chromosome inactivation with a critical role in driving cell fate decisions by trans-chromosomal interactions. Replicate RNA-Seq analyses of oligo-mediated knockdowns of linc-FIRRE and hnRNPU in two different cellular contexts; HeLa cells and mouse embryonic stem cells.
Project description:Long non-coding RNAs are important regulators of diverse biological prosesses. Here, we report on functional identification and characterization of a novel long intergenic noncoding RNA with MyoD-regulated and skeletal muscle-restricted expression that promotes the activation of the myogenic program, and is therefore termed Linc-RAM (Linc-RNA Activator of Myogenesis). Linc-RAM is transcribed from an intergenic region of myogenic cells and its expression is upregulated during myogenesis. Notably, in vivo functional studies show that Linc-RAM knockout mice display impaired muscle regeneration due to differentiation defect of satellite cells. Mechanistically, Linc-RAM regulates expression of myogenic genes by directly binding MyoD, which in turn promotes the assembly of the MyoD-Baf60c-Brg1 complex on the regulatory elements of target genes. Collectively, our findings reveal the functional role and molecular mechanism of a lineage-specific Linc-RAM as a regulatory lncRNA required for tissues-specific chromatin remodeling and gene expression.
Project description:To determine if induced p53 binding is associated with gene expression in genome-wide. We examined mRNA levels with the Affymetrix Human Exon 1.0 ST platform in human lymphoblastoid GM12878 cells treated with doxorubicin to activate p53. In response to various cellular stresses, the tumor suppressor gene p53 induces activation or repression of more than a thousand human genes. Selective binding and transactivation of a large potential pool of p53 response elements (REs) is believed to regulate the variation in stress response across stress types and between cell types. To elucidate how the human genome is targeted by p53 at the chromatin level, we mapped the genome-wide localization of p53 and H3K4me3 from Doxo-treated human lymphoblastoid cells, and examined the relationships among p53 occupancy, gene expression, H3K4me3, chromatin accessibility (DNase 1 Hypersensitivity, DHS), ENCODE chromatin states, RE sequence specificity and evolutionary conservation. Human lymphoblastoid (GM 12878) cells at a density of 900,000 cells/ml were prepared in triplicate for each time point and treated with 0.5 µM doxorubicin (Calbiochem) for 4, 18 hr or no treatment (at 0 time). Total RNA will be extracted from each culture (9 RNA samples) using the Qiagen RNeasy kit with DNase digestion. RNA was quantified using RiboGreen (Invitrogen), check for quality by OD and Bioanalyzer and stored at -80°C. Expression analysis was conducted at at NIEHS Microarray Core using Affymetrix Human Exon 1.0 ST arrays following the Affymetrix hybridization protocols. Exon expression data were analyzed through Affymetrix Expression Console using gene-level RMA summarization and sketch-quantile normalization methods.