scholarly journals The Lineage-Specific Transcription Factor PU.1 Prevents Polycomb-Mediated Heterochromatin Formation at Macrophage-Specific Genes

2015 ◽  
Vol 35 (15) ◽  
pp. 2610-2625 ◽  
Author(s):  
Mohita Tagore ◽  
Michael J. McAndrew ◽  
Alison Gjidoda ◽  
Monique Floer
Keyword(s):  
Nucleosome Occupancy ◽  
Regulatory Region ◽  
Regulatory Elements ◽  
External Signal ◽  
Distal Enhancer ◽  
Heterochromatin Formation ◽  
Polycomb Repressive Complex 2 ◽  
Transcriptional Regulatory Elements ◽  
Transcriptional Regulatory

Lineage-specific transcription factors (TFs) are important determinants of cellular identity, but their exact mode of action has remained unclear. Here we show using a macrophage differentiation system that the lineage-specific TF PU.1 keeps macrophage-specific genes accessible during differentiation by preventing Polycomb repressive complex 2 (PRC2) binding to transcriptional regulatory elements. We demonstrate that the distal enhancer of a gene becomes bound by PRC2 as cells differentiate in the absence of PU.1 binding and that the gene is wrapped into heterochromatin, which is characterized by increased nucleosome occupancy and H3K27 trimethylation. This renders the gene inaccessible to the transcriptional machinery and prevents induction of the gene in response to an external signal in mature cells. In contrast, if PU.1 is bound at the transcriptional regulatory region of a gene during differentiation, PRC2 is not recruited, nucleosome occupancy is kept low, and the gene can be induced in mature macrophages. Similar results were obtained at the enhancers of other macrophage-specific genes that fail to bind PU.1 as an estrogen receptor fusion (PUER) in this system. These results show that one role of PU.1 is to exclude PRC2 and to prevent heterochromatin formation at macrophage-specific genes.

Identification of transcriptional elements within the long terminal repeat of Rous sarcoma virus

1983 ◽  
Vol 3 (10) ◽  
pp. 1834-1845
Author(s):  
G M Gilmartin ◽  
J T Parsons
Keyword(s):  
Long Terminal Repeat ◽  
Virus Replication ◽  
Rous Sarcoma Virus ◽  
Regulatory Elements ◽  
Terminal Repeat ◽  
Tata Box ◽  
Transcriptional Regulatory Elements ◽  
Rous Sarcoma ◽  
Transcriptional Regulatory ◽  
Sarcoma Virus

Transcriptional regulatory elements within the Rous sarcoma virus long terminal repeat were examined by the construction of a series of deletions and small insertions within the U3 region of the long terminal repeat. The analysis of these mutations in chicken embryo cells and COS cells permitted the identification of important transcriptional regulatory elements. Sequences within the region 31 to 18 base pairs upstream of the RNA cap site (-31 to -18), encompassing a TATA box-like sequence, function in the selection of the correct site of transcription initiation and, in addition, augment the efficiency of transcription. These sequences are essential for virus replication. Sequences within the region -79 to -59, overlapping a CAAT box-like sequence, are not required for virus replication and have no obvious effect on viral RNA transcription in the presence of an intact TATA box. However, in mutants lacking a functional TATA sequence, mutations in this region serve to decrease the efficiency of correct transcriptional initiation events.

scholarly journals Systematic dissection of transcriptional regulatory networks by genome-scale and single-cell CRISPR screens

2021 ◽  
Vol 7 (27) ◽  
pp. eabf5733
Author(s):  
Rui Lopes ◽  
Kathleen Sprouffske ◽  
Caibin Sheng ◽  
Esther C. H. Uijttewaal ◽  
Adriana Emma Wesdorp ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Regulatory Networks ◽  
Essential Role ◽  
Regulatory Elements ◽  
Transcriptional Regulatory Networks ◽  
Transcriptional Regulatory Elements ◽  
Transcriptional Regulatory ◽  
Functional Relevance ◽  
Genome Scale ◽  
Transcription Program

Millions of putative transcriptional regulatory elements (TREs) have been cataloged in the human genome, yet their functional relevance in specific pathophysiological settings remains to be determined. This is critical to understand how oncogenic transcription factors (TFs) engage specific TREs to impose transcriptional programs underlying malignant phenotypes. Here, we combine cutting edge CRISPR screens and epigenomic profiling to functionally survey ≈15,000 TREs engaged by estrogen receptor (ER). We show that ER exerts its oncogenic role in breast cancer by engaging TREs enriched in GATA3, TFAP2C, and H3K27Ac signal. These TREs control critical downstream TFs, among which TFAP2C plays an essential role in ER-driven cell proliferation. Together, our work reveals novel insights into a critical oncogenic transcription program and provides a framework to map regulatory networks, enabling to dissect the function of the noncoding genome of cancer cells.

scholarly journals Elucidating the Regulatory Elements for Transcription Termination and Posttranscriptional Processing in the Streptomyces clavuligerus Genome

mSystems ◽  
2021 ◽  
Vol 6 (3) ◽  
Author(s):  
Soonkyu Hwang ◽  
Namil Lee ◽  
Donghui Choe ◽  
Yongjae Lee ◽  
Woori Kim ◽  
...  
Keyword(s):  
Secondary Metabolite ◽  
Transcription Termination ◽  
Gene Clusters ◽  
Streptomyces Clavuligerus ◽  
Regulatory Elements ◽  
Regulation Of Transcription ◽  
Content Type ◽  
Transcriptional Regulatory Elements ◽  
Transcriptional Regulatory ◽  
Posttranscriptional Processing

ABSTRACT Identification of transcriptional regulatory elements in the GC-rich Streptomyces genome is essential for the production of novel biochemicals from secondary metabolite biosynthetic gene clusters (smBGCs). Despite many efforts to understand the regulation of transcription initiation in smBGCs, information on the regulation of transcription termination and posttranscriptional processing remains scarce. In this study, we identified the transcriptional regulatory elements in β-lactam antibiotic-producing Streptomyces clavuligerus ATCC 27064 by determining a total of 1,427 transcript 3′-end positions (TEPs) using the term-seq method. Termination of transcription was governed by three classes of TEPs, of which each displayed unique sequence features. The data integration with transcription start sites and transcriptome data generated 1,648 transcription units (TUs) and 610 transcription unit clusters (TUCs). TU architecture showed that the transcript abundance in TU isoforms of a TUC was potentially affected by the sequence context of their TEPs, suggesting that the regulatory elements of TEPs could control the transcription level in additional layers. We also identified TU features of a xenobiotic response element (XRE) family regulator and DUF397 domain-containing protein, particularly showing the abundance of bidirectional TEPs. Finally, we found that 189 noncoding TUs contained potential cis- and trans-regulatory elements that played a major role in regulating the 5′ and 3′ UTR. These findings highlight the role of transcriptional regulatory elements in transcription termination and posttranscriptional processing in Streptomyces sp. IMPORTANCE Streptomyces sp. is a great source of bioactive secondary metabolites, including antibiotics, antifungal agents, antiparasitic agents, immunosuppressant compounds, and other drugs. Secondary metabolites are synthesized via multistep conversions of the precursor molecules from primary metabolism, governed by multicomplex enzymes from secondary metabolite biosynthetic gene clusters. As their production is closely related with the growth phase and dynamic cellular status in response to various intra- and extracellular signals, complex regulatory systems tightly control the gene expressions related to secondary metabolism. In this study, we determined genome-wide transcript 3′-end positions and transcription units in the β-lactam antibiotic producer Streptomyces clavuligerus ATCC 27064 to elucidate the transcriptional regulatory elements in transcription termination and posttranscriptional processing by integration of multiomics data. These unique features, such as transcript 3′-end sequence, potential riboregulators, and potential 3′-untranslated region (UTR) cis-regulatory elements, can be potentially used to design engineering tools that can regulate the transcript abundance of genes for enhancing secondary metabolite production.

Accurate Identification of Active Transcriptional Regulatory Elements from Global Run-On and Sequencing Data

2014 ◽  
Author(s):  
Charles G Danko ◽  
Stephanie L Hyland ◽  
Leighton J Core ◽  
Andre L Martins ◽  
Colin T Waters ◽  
...  
Keyword(s):  
Multiple Scales ◽  
Regulatory Element ◽  
Cell Types ◽  
Regulatory Elements ◽  
Support Vector ◽  
Sequencing Data ◽  
Accurate Identification ◽  
Single Experiment ◽  
Transcriptional Regulatory Elements ◽  
Transcriptional Regulatory

Identification of the genomic regions that regulate transcription remains an important open problem. We have recently shown that global run-on and sequencing (GRO-seq) with enrichment for 5′-capped RNAs reveals patterns of divergent transcription that accurately mark active transcriptional regulatory elements (TREs), including enhancers and promoters. Here, we demonstrate that active TREs can be identified with comparable accuracy by applying sensitive machine-learning methods to standard GRO-seq and PRO-seq data, allowing TREs to be assayed together with transcription levels, elongation rates, and other transcriptional features, in a single experiment. Our method, called discriminative Regulatory Element detection from GRO-seq (dREG), summarizes GRO-seq read counts at multiple scales and uses support vector regression to predict active TREs. The predicted TREs are strongly enriched for marks associated with functional elements, including H3K27ac, transcription factor binding sites, eQTLs, and GWAS-associated SNPs. Using dREG, we survey TREs in eight cell types and provide new insights into global patterns of TRE assembly and function.

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