Project description:Impaired or excessive growth of endothelial cells contributes to several diseases. However, the functional involvement of regulatory long non-coding RNAs in these processes is not well defined. Here we show that the long non-coding antisense transcript of GATA6 (GATA6-AS) interacts with the epigenetic regulator LOXL2 to regulates endothelial gene expression via changes in histone methylation. Using RNA deep sequencing, we find that GATA6-AS is up-regulated in endothelial cells during hypoxia. Silencing of GATA6-AS diminishes TGF-β2-induced endothelial-mesenchymal transition in vitro and promotes formation of blood vessels in mice. We identify LOXL2, known to remove activating H3K4me3 chromatin marks, as a GATA6-AS-associated protein, and reveal a set of angiogenesis-related genes that are inversely regulated by LOXL2 and GATA6-AS silencing. As GATA6-AS silencing reduces H3K4me3 methylation of two of these genes, periostin and cyclooxygenase-2, we conclude that GATA6-AS acts as negative regulator of nuclear LOXL2 function. In this dataset we include the global gene expression analysis using exon arrays after silencing LOXL2.
Project description:Impaired or excessive growth of endothelial cells contributes to several diseases. However, the functional involvement of regulatory long non-coding RNAs in these processes is not well defined. Here we show that the long non-coding antisense transcript of GATA6 (GATA6-AS) interacts with the epigenetic regulator LOXL2 to regulates endothelial gene expression via changes in histone methylation. Using RNA deep sequencing, we find that GATA6-AS is up-regulated in endothelial cells during hypoxia. Silencing of GATA6-AS diminishes TGF-β2-induced endothelial-mesenchymal transition in vitro and promotes formation of blood vessels in mice. We identify LOXL2, known to remove activating H3K4me3 chromatin marks, as a GATA6-AS-associated protein, and reveal a set of angiogenesis-related genes that are inversely regulated by LOXL2 and GATA6-AS silencing. As GATA6-AS silencing reduces H3K4me3 methylation of two of these genes, periostin and cyclooxygenase-2, we conclude that GATA6-AS acts as negative regulator of nuclear LOXL2 function. In this dataset we include the global gene expression analysis using exon arrays after silencing the lncRNA GATA6-AS.
Project description:Impaired or excessive growth of endothelial cells contributes to several diseases. However, the functional involvement of regulatory long non-coding RNAs in these processes is not well defined. Here we show that the long non-coding antisense transcript of GATA6 (GATA6-AS) interacts with the epigenetic regulator LOXL2 to regulate endothelial gene expression via changes in histone methylation. Using RNA deep sequencing, we find that GATA6-AS is up-regulated in endothelial cells during hypoxia. Silencing of GATA6-AS diminishes TGF-?2-induced endothelial-mesenchymal transition in vitro and promotes formation of blood vessels in mice. We identify LOXL2, known to remove activating H3K4me3 chromatin marks, as a GATA6-AS-associated protein, and reveal a set of angiogenesis-related genes that are inversely regulated by LOXL2 and GATA6-AS silencing. As GATA6-AS silencing reduces H3K4me3 methylation of two of these genes, periostin and cyclooxygenase-2, we conclude that GATA6-AS acts as negative regulator of nuclear LOXL2 function.
Project description:Transcriptional gene silencing by small interfering RNAs (siRNAs) has been widely described in various species, such as plants or fission yeasts. In mammals, its extent remained somewhat debated. Previous studies showed that siRNAs targeting gene promoters can induce the silencing of the targeted promoter, although the involvement of off-target mechanisms was also suggested. Here, by nascent RNA capture and RNA Pol II ChIP, we show that siRNAs targeting a chromatin-associated non-coding RNA induce its transcriptional silencing. Deletion of the sequence targeted by one of these siRNAs on the two alleles by genome editing further show that this silencing is due to base pairing of the siRNA to the target. Moreover, by using cells with heterozygous deletion of the target sequence, we show that only the wild type allele, but not the deleted allele, is silenced by the siRNA, indicating that transcriptional silencing occurs only in cis. Finally, we demonstrate that both Ago1 and Ago2 are involved in this transcriptional silencing. Altogether, our data demonstrate that siRNAs targeting a chromatin-associated RNA at distance from its promoter induce its transcriptional silencing. Our results thus extend the possible repertoire of endogenous or exogenous interfering RNAs.
Project description:Esophageal cancer is the sixth most common cause of cancer death globally, of which esophageal squamous cell carcinoma (ESCC) is the most common histological subtype. High level expression of LOXL2 has been shown to be associated with tumor metastasis and poor clinical outcome in ESCC. To determine whether there are genes whose expression in ESCC cells is regulated by LOXL2, next generation RNA sequencing analysis was used to compare the RNA expression profile of KYSE510 cells before and after silencing LOXL2 expression.
Project description:Our results indicate that oxidation of TAF10 by LOXL2 induces its release from its promoters, leading to a block in TFIID-dependent gene transcription. Since TFIID complex is crucial for the expression of Nanog, Klf4, Sox2 and Oct4 and for maintaining the pluripotent state of embryonic stem cells, TAF10 oxidation by LOXL2 leads to inactivation of the pluripotency genes and a loss of pluripotent capacity in embryonic stem cells. Moreover, in vivo results demonstrate an essential role of LOXL2 in neural differentiation during zebrafish development: in the absence of LOXL2 the neural progenitor gene Sox2 is aberrantly overexpressed and neural differentiation is impaired. 12 samples were analyzed: mES transduced with control shRNA (n=3); mES transduced with LOXL2 shRNA (n=3), ES transduced with control shRNA and treated with RA (n=3); ES transduced with LOXL2 shRNA and treated with RA (n=3)
Project description:In plants, small interfering RNAs (siRNAs) are a quintessential class of RNA interference (RNAi)-inducing molecules produced by the endonucleolytic cleavage of double stranded RNAs (dsRNAs). In order to ensure robust RNAi, siRNAs are amplified through a positive feedback mechanism called transitivity. Transitivity relies on RNA-DIRECTED-RNA POLYMERASE 6 (RDR6)-mediated dsRNA synthesis using siRNA-targeted RNA. The newly synthesized dsRNA is subsequently cleaved into secondary siRNAs by DICER-LIKE (DCL) endonucleases. Just like primary siRNAs, secondary siRNAs are also loaded into ARGONAUTE proteins (AGOs) to form an RNA-induced silencing complex (RISC) reinforcing the cleavage of the target RNA. Although the molecular players underlying transitivity are well established, the mode of action of transitivity remains elusive. In this study, we investigated the influence of primary target sites on transgene silencing and transitivity using the GFP-expressing Nicotiana benthamiana 16C line, high pressure spraying protocol (HPSP), and synthetic 22-nucleotide (nt) long siRNAs. We found that the 22-nt siRNA targeting the 3’ of the GFP transgene was less efficient in inducing silencing when compared to the siRNAs targeting the 5’ and middle region of the GFP. Moreover, sRNA sequencing of locally silenced leaves showed that the amount but not the profile of secondary RNAs is shaped by the occupancy of the primary siRNA triggers on the target RNA. Our findings suggest that RDR6-mediated dsRNA synthesis is not primed by primary siRNAs and that dsRNA synthesis appears to be generally initiated at the 3’ end of the target RNA.
Project description:Our results indicate that oxidation of TAF10 by LOXL2 induces its release from its promoters, leading to a block in TFIID-dependent gene transcription. Since TFIID complex is crucial for the expression of Nanog, Klf4, Sox2 and Oct4 and for maintaining the pluripotent state of embryonic stem cells, TAF10 oxidation by LOXL2 leads to inactivation of the pluripotency genes and a loss of pluripotent capacity in embryonic stem cells. Moreover, in vivo results demonstrate an essential role of LOXL2 in neural differentiation during zebrafish development: in the absence of LOXL2 the neural progenitor gene Sox2 is aberrantly overexpressed and neural differentiation is impaired.