scholarly journals Cis-acting lnc-eRNA SEELA directly binds histone H4 to promote histone recognition and leukemia progression

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Ke Fang ◽  
Wei Huang ◽  
Yu-Meng Sun ◽  
Tian-Qi Chen ◽  
Zhan-Cheng Zeng ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Cancer Metabolism ◽  
Chromosomal Translocation ◽  
Underlying Mechanism ◽  
Histone H4 ◽  
Transcription Control ◽  
Hoxa Cluster ◽  
Enhancer Activity ◽  
Cis Acting ◽  
Cancer Initiation

Abstract Background Long noncoding enhancer RNAs (lnc-eRNAs) are a subset of stable eRNAs identified from annotated lncRNAs. They might act as enhancer activity-related therapeutic targets in cancer. However, the underlying mechanism of epigenetic activation and their function in cancer initiation and progression remain largely unknown. Results We identify a set of lncRNAs as lnc-eRNAs according to the epigenetic signatures of enhancers. We show that these lnc-eRNAs are broadly activated in MLL-rearranged leukemia (MLL leukemia), an aggressive leukemia caused by a chromosomal translocation, through a mechanism by which the HOXA cluster initiates enhancer activity, and the epigenetic reader BRD4 cooperates with the coregulator MLL fusion oncoprotein to induce transcriptional activation. To demonstrate the functional roles of lnc-eRNAs, two newly identified lnc-eRNAs transcribed from the SEELA eRNA cluster (SEELA), SEELA1 and SEELA2, are chosen for further studies. The results show that SEELA mediated cis-activated transcription of the nearby oncogene Serine incorporate 2 (SERINC2) by directly binding to the K31 amino acid (aa) of histone H4. Chromatin-bound SEELA strengthens the interaction between chromatin and histone modifiers to promote histone recognition and oncogene transcription. Further studies show that the SEELA-SERINC2 axis regulated aspects of cancer metabolism, such as sphingolipid synthesis, to affect leukemia progression. Conclusions This study shows that lnc-eRNAs are epigenetically activated by cancer-initiating oncoproteins and uncovers a cis-activating mechanism of oncogene transcription control based on lnc-eRNA-mediated epigenetic regulation of enhancer activity, providing insights into the critical roles of lnc-eRNAs in cancer initiation and progression.

Insights into Enhancer RNAs: Biogenesis and Emerging Role in Brain Diseases

2021 ◽  
pp. 107385842110468
Author(s):  
Yuxin Shen ◽  
Zhengyi Huang ◽  
Ruiqing Yang ◽  
Yunlong Chen ◽  
Qiang Wang ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Small Proportion ◽  
Target Genes ◽  
Noncoding Rnas ◽  
Histone Mark ◽  
Brain Diseases ◽  
Enhancer Activity ◽  
Cis Acting ◽  
High Level ◽  
Classification Function

Enhancers are cis-acting elements that control the transcription of target genes and are transcribed into a class of noncoding RNAs (ncRNAs) termed enhancer RNAs (eRNAs). eRNAs have shorter half-lives than mRNAs and long noncoding RNAs; however, the frequency of transcription of eRNAs is close to that of mRNAs. eRNA expression is associated with a high level of histone mark H3K27ac and a low level of H3K27me3. Although eRNAs only account for a small proportion of ncRNAs, their functions are important. eRNAs can not only increase enhancer activity by promoting the formation of enhancer-promoter loops but also regulate transcriptional activation. Increasing numbers of studies have found that eRNAs play an important role in the occurrence and development of brain diseases; however, further research into eRNAs is required. This review discusses the concept, characteristics, classification, function, and potential roles of eRNAs in brain diseases.

scholarly journals Bromodomain analysis of Brd2-dependent transcriptional activation of cyclin A1

2005 ◽  
Vol 387 (1) ◽  
pp. 257-269 ◽  
Author(s):  
Anupama SINHA ◽  
Douglas V. FALLER ◽  
Gerald V. DENIS
Keyword(s):  
Cell Cycle ◽  
Transcription Factors ◽  
Transcriptional Activation ◽  
Transcriptional Repression ◽  
Cyclin A ◽  
S Phase ◽  
Histone H4 ◽  
Transcription Control ◽  
Histone H4 Acetylation ◽  
E2f Transcription Factors

Cyclin A is regulated primarily through transcription control during the mammalian cell cycle. A dual mechanism of cyclin A transcriptional repression involves, on the one hand, promoter-bound inhibitory complexes of E2F transcription factors and RB (retinoblastoma) family proteins, and on the other, chromatin-directed histone deacetylase activity that is recruited to the cyclin A promoter early in the cell cycle in association with these RB proteins. This dual regulation maintains transcriptional silence of the cyclin A locus until its transcription is required in S-phase. At that time, RB family members dissociate from E2F proteins and nucleosomal restructuring of the locus takes place, to permit transcriptional activation and resultant S-phase progression to proceed. We have identified a double bromo-domain-containing protein Brd2, which exhibits apparent ‘scaffold’ or transcriptional adapter functions and mediates recruitment of both E2F transcription factors and chromatin-remodelling activity to the cyclin A promoter. We have shown previously that Brd2-containing nuclear, multiprotein complexes contain E2F-1 and -2. In the present study, we show that, in S-phase, they also contain histone H4-directed acetylase activity. Overexpression of Brd2 in fibroblasts accelerates the cell cycle through increased expression of cyclin A and its associated cyclin-dependent kinase activity. Chromatin immunoprecipitation studies show that Brd2 is physically present at the cyclin A promoter and its overexpression promotes increased histone H4 acetylation at the promoter as it becomes transcriptionally active, suggesting a new model for the dual regulation of cyclin A.

scholarly journals Dynamic histone acetylation in floral volatile synthesis and emission in petunia flowers

2021 ◽  
Author(s):  
Ryan M Patrick ◽  
Xing-Qi Huang ◽  
Natalia Dudareva ◽  
Ying Li
Keyword(s):  
Transcriptional Activation ◽  
Metabolic Pathways ◽  
Transcriptional Repression ◽  
Metabolic Networks ◽  
Underlying Mechanism ◽  
Expression Of Genes ◽  
Genome Wide ◽  
Chemical Inhibitors ◽  
Volatile Organic ◽  
Floral Volatile

Abstract Biosynthesis of secondary metabolites relies on primary metabolic pathways to provide precursors, energy, and cofactors, thus requiring coordinated regulation of primary and secondary metabolic networks. However, to date, it remains largely unknown how this coordination is achieved. Using Petunia hybrida flowers, which emit high levels of phenylpropanoid/benzenoid volatile organic compounds (VOCs), we uncovered genome-wide dynamic deposition of histone H3 lysine 9 acetylation (H3K9ac) during anthesis as an underlying mechanism to coordinate primary and secondary metabolic networks. The observed epigenome reprogramming is accompanied by transcriptional activation at gene loci involved in primary metabolic pathways that provide precursor phenylalanine, as well as secondary metabolic pathways to produce volatile compounds. We also observed transcriptional repression among genes involved in alternative phenylpropanoid branches that compete for metabolic precursors. We show that GNAT family histone acetyltransferase(s) (HATs) are required for the expression of genes involved in VOC biosynthesis and emission, by using chemical inhibitors of HATs, and by knocking down a specific HAT gene, ELP3, through transient RNAi. Together, our study supports that regulatory mechanisms at chromatin level may play an essential role in activating primary and secondary metabolic pathways to regulate VOC synthesis in petunia flowers.

scholarly journals The initiation and pattern of spread of histone H4 acetylation parallel the order of transcriptional activation of genes in the aflatoxin cluster

2007 ◽  
Vol 66 (3) ◽  
pp. 713-726 ◽  
Author(s):  
Ludmila V. Roze ◽  
Anna E. Arthur ◽  
Sung-Yong Hong ◽  
Anindya Chanda ◽  
John E. Linz
Keyword(s):  
Transcriptional Activation ◽  
Histone H4 ◽  
Histone H4 Acetylation

A gene product needed for induction of allantoin system genes in Saccharomyces cerevisiae but not for their transcriptional activation

1989 ◽  
Vol 9 (9) ◽  
pp. 3869-3877
Author(s):  
P A Bricmont ◽  
T G Cooper
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Product ◽  
Transcriptional Activation ◽  
Nitrogen Catabolite Repression ◽  
Wild Type ◽  
Product Analysis ◽  
Cis Acting ◽  
Induction Sequence ◽  
Basal Level Expression ◽  
Activation Sequence

The allantoin-degradative pathway of Saccharomyces cerevisiae consists of several genes whose expression is highly induced by the presence of allophanic acid. Induced expression requires a functional DAL81 gene product. Analysis of these genes has demonstrated the presence of three cis-acting elements in the upstream regions: (i) an upstream activation sequence (UAS) required for transcriptional activation in an inducer-independent fashion, (ii) an upstream repression sequence (URS) that mediates inhibition of this transcriptional activation, and (iii) an upstream induction sequence (UIS) needed for a response to inducer. The UIS element mediates inhibition of URS-mediated function when inducer is present. We cloned and characterized the DAL81 gene and identified the element with which it was associated. The gene was found to encode a rare 3.2-kilobase-pair mRNA. The amount of DAL81-specific RNA responded neither to induction nor to nitrogen catabolite repression. Deletion of the DAL81 gene resulted in loss of induction but did not significantly affect basal level expression of the DAL7 and DUR1,2 genes or the UAS and URS functions present in plasmid constructions. These data suggest that (i) transcriptional activation of the DAL genes and their responses to inducer are mediated by different factors and cis-acting sequences and (ii) the UIS functions only when a wild-type DAL81 gene product is available.

The Aspergillus nidulans abaA gene encodes a transcriptional activator that acts as a genetic switch to control development

1994 ◽  
Vol 14 (4) ◽  
pp. 2503-2515
Author(s):  
A Andrianopoulos ◽  
W E Timberlake
Keyword(s):  
Aspergillus Nidulans ◽  
Transcriptional Activation ◽  
Expression System ◽  
Regulatory Gene ◽  
Binding Motif ◽  
Mobility Shift ◽  
Genetic Switch ◽  
Regulatory Regions ◽  
Cis Acting ◽  
Gel Mobility Shift

The Aspergillus nidulans abaA gene encodes a protein containing an ATTS DNA-binding motif and is required for the terminal stages of conidiophore development. Results from gel mobility shift and protection, missing-contact, and interference footprint assays showed that AbaA binds to the sequence 5'-CATTCY-3', where Y is a pyrimidine, making both major- and minor-groove contacts. Multiple AbaA binding sites are present in the cis-acting regulatory regions of several developmentally controlled structural genes as well as those of the upstream regulatory gene brlA, the downstream regulatory gene wetA, and abaA itself. These cis-acting regulatory regions confer AbaA-dependent transcriptional activation in a heterologous Saccharomyces cerevisiae gene expression system. From these observations, we propose that the AbaA transcription factor establishes a novel set of feedback regulatory loops responsible for determination of conidiophore development.

Analysis of a tissue-specific enhancer: ARF6 regulates adipogenic gene expression

1992 ◽  
Vol 12 (3) ◽  
pp. 1202-1208
Author(s):  
R A Graves ◽  
P Tontonoz ◽  
B M Spiegelman
Keyword(s):  
Gene Expression ◽  
Cultured Cells ◽  
Mutational Analysis ◽  
Cell Types ◽  
Specific Gene ◽  
Enhancer Activity ◽  
Cis Acting ◽  
Specific Gene Expression ◽  
Nuclear Extracts ◽  
Adipogenic Gene

The molecular basis of adipocyte-specific gene expression is not well understood. We have previously identified a 518-bp enhancer from the adipocyte P2 gene that stimulates adipose-specific gene expression in both cultured cells and transgenic mice. In this analysis of the enhancer, we have defined and characterized a 122-bp DNA fragment that directs differentiation-dependent gene expression in cultured preadipocytes and adipocytes. Several cis-acting elements have been identified and shown by mutational analysis to be important for full enhancer activity. One pair of sequences, ARE2 and ARE4, binds a nuclear factor (ARF2) present in extracts derived from many cell types. Multiple copies of these elements stimulate gene expression from a minimal promoter in preadipocytes, adipocytes, and several other cultured cell lines. A second pair of elements, ARE6 and ARE7, binds a separate factor (ARF6) that is detected only in nuclear extracts derived from adipocytes. The ability of multimers of ARE6 or ARE7 to stimulate promoter activity is strictly adipocyte specific. Mutations in the ARE6 sequence greatly reduce the activity of the 518-bp enhancer. These data demonstrate that several cis- and trans-acting components contribute to the activity of the adipocyte P2 enhancer and suggest that ARF6, a novel differentiation-dependent factor, may be a key regulator of adipogenic gene expression.

scholarly journals Specific repression of the yeast silent mating locus HMR by an adjacent telomere.

1994 ◽  
Vol 14 (1) ◽  
pp. 446-455 ◽  
Author(s):  
J S Thompson ◽  
L M Johnson ◽  
M Grunstein
Keyword(s):  
Mating Type ◽  
Chromosomal Location ◽  
Regulatory Genes ◽  
Histone H4 ◽  
Cis Acting ◽  
N Terminus ◽  
Silencer Elements ◽  
Chromosome Iii

The yeast silent mating loci HML and HMR are located at opposite ends of chromosome III adjacent to the telomeres. Mutations in the N terminus of histone H4 have been previously found to derepress the yeast silent mating locus HML to a much greater extent than HMR. Although differences in the a and alpha mating-type regulatory genes and in the cis-acting silencer elements do not appear to strongly influence the level of derepression at HMR, we have found that the differential between the two silent cassettes is largely due to the position of the HMR cassette relative to the telomere on chromosome III. While HML is derepressed to roughly the same extent by mutations in histone H4 regardless of its chromosomal location, HMR is affected to different extends depending upon its chromosomal positioning. We have found that HMR is more severely derepressed by histone H4 mutations when positioned far from the telomere (cdc14 locus on chromosome VI) but is only minimally affected by the same mutations when integrated immediately adjacent to another telomere (ADH4 locus on chromosome VII). These data indicate that the degree of silencing at HMR is regulated in part by its neighboring telomere over a distance of at least 23 kb and that this form of regulation is unique for HMR and not present at HML. These data also indicate that histone H4 plays an important role in regulating the silenced state at both HML and HMR.

scholarly journals miR-93-5p Suppresses Ovarian Cancer Malignancy and Negatively Regulate CCND2 By Binding To Its 3’UTR Region

2021 ◽  
Author(s):  
Guotong Chen ◽  
Yiwei Yan ◽  
Xiaojv Qiu ◽  
Chengfeng Ye ◽  
Xingmei Jiang ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Ovarian Cancer Patient ◽  
Apoptotic Cell ◽  
Gynecological Cancer ◽  
Underlying Mechanism ◽  
Bioinformatic Analysis ◽  
Cell Analysis ◽  
Wound Healing Assay ◽  
Cancer Initiation ◽  
Favorable Prognostic Factor

Abstract Ovarian cancer is the most lethal gynecological cancer worldwide, but the underlying mechanism of ovarian cancer malignancy acquirement is largely unknown. miRNA is ubiquitously implicated in disease especially in cancer initiation and progression. In current study, we firstly detected the expression level of miR-93-5p in ovarian cancer patient samples and conducted a survival analysis. Our data revealed miR-93-5p is a favorable prognostic factor but is downregulated in ovarian cancer patients. Secondly, CCK8 assay wound healing assay and flow cytometry-based cell cycle analysis and apoptotic cell analysis were performed respectively to study the function of miR-93-5p. Functional analysis show miR-93-5p promotes ovarian cancer malignancy in term of cell proliferation, migration but reduce cell death. Bioinformatic analysis showed Cyclin-D2(CCND2) is a candidate gene of miR-93-5p with the binding site in its 3’UTR region. Furthermore, quantitive-PCR and western blot were utilized to measure miR-93-5p, CCND2 levels in tissues samples and cell lines. Our data suggested miR-93-5p is negatively correlated to the level of CCND2 mRNA and protein. Finally, Luciferase report assay was conducted, and we demonstrated miR-93-5p reduces CCND2 expression by binding to the 3’UTR region. Our study revealed the function of miR-93-5p in ovarian cancer malignancy and declaimed CCND2 as a target of miR-93-5p.

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