scholarly journals The Human Adenovirus Type 5 L4 Promoter Is Negatively Regulated by TFII-I and L4-33K

2015 ◽  
Vol 89 (14) ◽  
pp. 7053-7063 ◽  
Author(s):  
Jordan Wright ◽  
Zeenah Atwan ◽  
Susan J. Morris ◽  
Keith N. Leppard
Keyword(s):  
Gene Expression ◽  
Transcription Start Site ◽  
Intermediate Phase ◽  
Late Phase ◽  
Human Adenovirus ◽  
Adenovirus Type ◽  
Negative Regulation ◽  
Start Site ◽  
Transcription Start ◽  
Adenovirus Type 5

ABSTRACTThe late phase of adenovirus gene expression is controlled by proteins made in the intermediate phase, including L4 proteins of 22,000- and 33,000-Da apparent molecular mass (L4-22K and -33K proteins) that are expressed initially from the L4 promoter (L4P). The L4P is activated by a combination of viral proteins and cellular p53 and is ultimately inhibited again by its own products. Here, we have examined the L4P of human adenovirus type 5 in detail and have defined its transcription start site, which our data suggest is positioned by a weak TATA box. Rather than contributing positively to promoter activity, a putative initiator element at the transcription start site acts as a target for negative regulation imposed on the L4P by cellular TFII-I. We show that this TFII-I inhibition is relieved by one of the previously defined viral activators of the L4P, the E4 Orf3 protein, which alters the pool of TFII-I in the cell. We also explore further the negative regulation of the L4P by its products and show that the L4-33K protein is more significant in this process than L4-22K. It is the combined actions of positive and negative factors that lead to the transient activation of the L4P at the onset of the late phase of adenovirus gene expression.IMPORTANCEThe adenovirus replication cycle proceeds through multiple phases of gene expression in which a key step is the activation of late-phase gene expression to produce proteins from which progeny particles can be formed. Working with human adenovirus type 5, we showed previously that two proteins expressed from the L4 region of the viral genome perform essential roles in moving the infection on into the late phase; these two proteins are produced by the action of a dedicated promoter, the L4P, and without them the infection does not proceed successfully to progeny generation. In this new work, we delineate further aspects of L4P activity and regulation. Understanding how the L4P works, and how it contributes to activation of the late phase of infection, is important to our understanding of natural infections by the virus, in which late gene expression can fail to occur, allowing the virus to persist.

scholarly journals Sequence of the 5′-flanking region and promoter activity of the human mucin gene MUC5B in different phenotypes of colon cancer cells

2000 ◽  
Vol 348 (3) ◽  
pp. 675-686 ◽  
Author(s):  
Isabelle VAN SEUNINGEN ◽  
Michaël PERRAIS ◽  
Pascal PIGNY ◽  
Nicole PORCHET ◽  
Jean-Pierre AUBERT
Keyword(s):  
Gene Expression ◽  
Transcription Start Site ◽  
Promoter Activity ◽  
Luciferase Reporter ◽  
Nuclear Factor ◽  
Start Site ◽  
Transcription Start ◽  
Mucin Gene ◽  
Intron 1 ◽  
Flanking Region

Control of gene expression in intestinal cells is poorly understood. Molecular mechanisms that regulate transcription of cellular genes are the foundation for understanding developmental and differentiation events. Mucin gene expression has been shown to be altered in many intestinal diseases and especially cancers of the gastrointestinal tract. Towards understanding the transcriptional regulation of a member of the 11p15.5 human mucin gene cluster, we have characterized 3.55 kb of the 5ʹ-flanking region of the human mucin gene MUC5B, including the promoter, the first two exons and the first intron. We report here the promoter activity of successively 5ʹ-truncated sections of 956 bases of this region by fusing it to the coding region of a luciferase reporter gene. The transcription start site was determined by primer-extension analysis. The region upstream of the transcription start site is characterized by the presence of a TATA box at bases -32/-26, DNA-binding elements for transcription factors c-Myc, N-Myc, Sp1 and nuclear factor ĸB as well as putative activator protein (AP)-1-, cAMP-response-element-binding protein (CREB)-, hepatocyte nuclear factor (HNF)-1-, HNF-3-, TGT3-, gut-enriched Krüppel factor (GKLF)-, thyroid transcription factor (TTF)-1- and glucocorticoid receptor element (GRE)-binding sites. Intron 1 of MUC5B was also characterized, it is 2511 nucleotides long and contains a DNA segment of 259 bp in which are clustered eight tandemly repeated GA boxes and a CACCC box that bind Sp1. AP-2α and GATA-1 nuclear factors were also shown to bind to their respective cognate elements in intron 1. In transfection studies the MUC5B promoter showed a cell-specific activity as it is very active in mucus-secreting LS174T cells, whereas it is inactive in Caco-2 enterocytes and HT-29 STD (standard) undifferentiated cells. Within the promoter, maximal transcription activity was found in a segment covering the first 223 bp upstream of the transcription start site. Finally, in co-transfection experiments a transactivating effect of Sp1 on to MUC5B promoter was seen in LS174T and Caco-2 cells.

scholarly journals Comparative Sequence Analysis of the Largest E1A Proteins of Human and Simian Adenoviruses

2002 ◽  
Vol 76 (16) ◽  
pp. 7968-7975 ◽  
Author(s):  
Nikita Avvakumov ◽  
Russ Wheeler ◽  
Jean Claude D'Halluin ◽  
Joe S. Mymryk
Keyword(s):  
Gene Expression ◽  
Human Adenovirus ◽  
Detailed Comparison ◽  
Adenovirus Type ◽  
Comparative Sequence Analysis ◽  
Regulatory Proteins ◽  
Carboxyl Terminus ◽  
Adenovirus E1a ◽  
Simian Adenovirus ◽  
Adenovirus Type 5

ABSTRACT The early region 1A (E1A) gene is the first gene expressed after infection with adenovirus and has been most extensively characterized in human adenovirus type 5 (hAd5). The E1A proteins interact with numerous cellular regulatory proteins, influencing a variety of transcriptional and cell cycle events. For this reason, these multifunctional proteins have been useful as tools for dissecting pathways regulating cell growth and gene expression. Despite the large number of studies using hAd5 E1A, relatively little is known about the function of the E1A proteins of other adenoviruses. In 1985, a comparison of E1A sequences from three human and one simian adenovirus identified three regions with higher overall levels of sequence conservation designated conserved regions (CR) 1, 2, and 3. As expected, these regions are critical for a variety of E1A functions. Since that time, the sequences of several other human and simian adenovirus E1A proteins have been determined. Using these, and two additional sequences that we determined, we report here a detailed comparison of the sequences of 15 E1A proteins representing each of the six hAd subgroups and several simian adenoviruses. These analyses refine the positioning of CR1, 2, and 3; define a fourth CR located near the carboxyl terminus of E1A; and suggest several new functions for E1A.

scholarly journals Adenovirus Late-Phase Infection Is Controlled by a Novel L4 Promoter

2010 ◽  
Vol 84 (14) ◽  
pp. 7096-7104 ◽  
Author(s):  
Susan J. Morris ◽  
Gillian E. Scott ◽  
Keith N. Leppard
Keyword(s):  
Gene Expression ◽  
Intermediate Phase ◽  
Expression Patterns ◽  
Late Phase ◽  
Adenovirus Vector ◽  
Human Adenovirus ◽  
Late Gene ◽  
Genome Replication ◽  
Late Gene Expression ◽  
Viral Genome Replication

ABSTRACT During human adenovirus 5 infection, a temporal cascade of gene expression leads ultimately to the production of large amounts of the proteins needed to construct progeny virions. However, the mechanism for the activation of the major late gene that encodes these viral structural proteins has not been well understood. We show here that two key positive regulators of the major late gene, L4-22K and L4-33K, previously thought to be expressed under the control of the major late promoter itself, initially are expressed from a novel promoter that is embedded within the major late gene and dedicated to their expression. This L4 promoter is required for late gene expression and is activated by a combination of viral protein activators produced during the infection, including E1A, E4 Orf3, and the intermediate-phase protein IVa2, and also by viral genome replication. This new understanding redraws the long-established view of how adenoviral gene expression patterns are controlled and offers new ways to manipulate that gene expression cascade for adenovirus vector applications.

scholarly journals Alpha-thalassemia resulting from deletion of regulatory sequences far upstream of the alpha-globin structural genes

Blood ◽  
1991 ◽  
Vol 78 (6) ◽  
pp. 1589-1595
Author(s):  
L Romao ◽  
L Osorio-Almeida ◽  
DR Higgs ◽  
J Lavinha ◽  
SA Liebhaber
Keyword(s):  
Gene Expression ◽  
Transcription Start Site ◽  
Globin Gene ◽  
Regulatory Sequences ◽  
Start Site ◽  
Structural Genes ◽  
Transcription Start ◽  
Alpha Thalassemia ◽  
Alpha Globin ◽  
Globin Gene Expression

We describe an alpha-thalassemia determinant in which alpha-globin expression is silenced by a deletion located 27 kb 5′ to the transcription start site of the alpha 2-globin gene. This alpha- thalassemic determinant, (alpha alpha)MM, is a member of a newly described group of thalassemic mutations resulting from deletion of locus-controlling sequences critical to globin gene expression.

scholarly journals A Chinese hamster transcription start site atlas that enables targeted editing of CHO cells

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Isaac Shamie ◽  
Sascha H Duttke ◽  
Karen J la Cour Karottki ◽  
Claudia Z Han ◽  
Anders H Hansen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Start Site ◽  
Cho Cells ◽  
Genome Engineering ◽  
Chinese Hamster ◽  
Regulatory Elements ◽  
Start Site ◽  
Transcription Start ◽  
Transcription Start Sites ◽  
Silent Genes

Abstract Chinese hamster ovary (CHO) cells are widely used for producing biopharmaceuticals, and engineering gene expression in CHO is key to improving drug quality and affordability. However, engineering gene expression or activating silent genes requires accurate annotation of the underlying regulatory elements and transcription start sites (TSSs). Unfortunately, most TSSs in the published Chinese hamster genome sequence were computationally predicted and are frequently inaccurate. Here, we use nascent transcription start site sequencing methods to revise TSS annotations for 15 308 Chinese hamster genes and 3034 non-coding RNAs based on experimental data from CHO-K1 cells and 10 hamster tissues. We further capture tens of thousands of putative transcribed enhancer regions with this method. Our revised TSSs improves upon the RefSeq annotation by revealing core sequence features of gene regulation such as the TATA box and the Initiator and, as exemplified by targeting the glycosyltransferase gene Mgat3, facilitate activating silent genes by CRISPRa. Together, we envision our revised annotation and data will provide a rich resource for the CHO community, improve genome engineering efforts and aid comparative and evolutionary studies.

scholarly journals The histone variant macroH2A1.1 regulates gene expression by direct association with their transcription start site

2020 ◽  
Author(s):  
Ludmila Recoules ◽  
Alexandre Heurteau ◽  
Flavien Raynal ◽  
Fatima Moutahir ◽  
Fabienne Bejjani ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Cancer Cells ◽  
Transcription Start Site ◽  
Breast Cancer Cells ◽  
Molecular Mechanisms ◽  
Histone Variants ◽  
Histone Variant ◽  
Start Site ◽  
Transcription Start

AbstractThe histone variant macroH2A1 (mH2A1) is involved in cellular growth, differentiation and reprogramming, but the underlying molecular mechanisms are a matter of debate. Different roles of mH2A1 in gene expression may relate to functional differences of its two splicing isoforms, mH2A1.1 and mH2A1.2. Here, we map for the first time genome-wide localization of endogenous mH2A1.1 and link the distribution of mH2A1.1 to control of gene expression in human breast cancer cells. In addition to localization shared with mH2A1.2 to facultative heterochromatin, mH2A1.1 specifically associates with regulatory elements required for gene activation, super-enhancers and promoters of highly expressed genes. Depending on the recruitment profile of mH2A1.1 to these elements, selective depletion of mH2A1.1 up- or downregulates its target genes. mH2A1.1 represses transcription when its binding is spread over the entire gene and promoter, and activates transcription when its binding is strictly confined to the transcription start site (TSS). Notably, RNA Polymerase II was frequently in pause at mH2A1.1-activated genes. Functionally, mH2A1.1-dependent regulation of a subset of paused genes impedes mammary tumor cell migration. Molecular mechanisms of mH2A1.1 function at the TSS uncovered by our study define an intriguing new mode of transcription regulation in cancer cells.Author SummaryControl of gene expression driving cellular functions from differentiation to epistasis and causing, when dysfunctional, uncountable diseases, relies on modifications of chromatin structure. One key element enabling chromatin plasticity is the replacement of canonical histones by histone variants. Among histone variants macroH2A1 (mH2A) is an extraordinary H2A variant possessing a large non-histone domain placed outside of the nucleosome. Two splicing isoforms, mH2A1.1 and mH2A1.2, are produced, but these are rarely studied separately because they only differ in a 30 amino acid region and are difficult to distinguish experimentally, which likely explains contradictory functions reported in the literature. Here, we take advantage of a mH2A1.1 specific antibody to generate the first genome-wide chromatin-associated map of this histone variant in the invasive breast cancer cells line MDA-MB231. We confirm that mH2A1.1, like mH2A1.2, is enriched at facultative heterochromatin in agreement with its reported role as a repressor. However, we discovered that unlike its splicing isoform, mH2A1.1 specifically binds to super-enhancers and the transcription start site of highly transcribed genes. mH2A1.1 is necessary for regulating transcription of these genes. At the cellular level, we demonstrate that mH2A1.1 inhibits migration capacity of highly metastatic breast cancer cells. Our study characterizes for the first time binding profiles of mH2A1.1 that are linked to regulation of gene expression, thereby providing a new molecular mechanisms which govern the plasticity of human tumor cells.

scholarly journals Cooperation of E2F-p130 and Sp1-pRb Complexes in Repression of the Chinese Hamster dhfr Gene

2001 ◽  
Vol 21 (4) ◽  
pp. 1121-1131 ◽  
Author(s):  
Young-Chae Chang ◽  
Sharon Illenye ◽  
Nicholas H. Heintz
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Transcription Start Site ◽  
Trichostatin A ◽  
Chinese Hamster ◽  
Serum Starvation ◽  
Start Site ◽  
Transcription Start ◽  
Serum Stimulation ◽  
Cell Extracts

ABSTRACT In mammalian cells reiterated binding sites for Sp1 and two overlapping and inverted E2F sites at the transcription start site regulate the dhfr promoter during the cell growth cycle. Here we have examined the contributions of the dhfr Sp1 and E2F sites in the repression of dhfr gene expression. In serum-starved cells or during serum stimulation, the Chinese hamsterdhfr gene was not derepressed by trichostatin A (TSA), an inhibitor of histone deacetylases (HDAC). Immunoprecipitation experiments showed that HDAC1 and hypophosphorylated retinoblastoma protein (pRb) are associated with Sp1 in serum-starved CHOC400 cells. In transfection experiments, reporter plasmids containing the reiterated dhfr Sp1 sites were stimulated 10-fold by TSA, while a promoter containing four dhfr E2F sites and a TATA box was responsive to E2F but was completely unaffected by TSA. HDAC1 did not coprecipitate with p130-E2F DNA binding complexes, the predominant E2F binding activity in cell extracts after serum starvation, suggesting that p130 imposes a TSA-insensitive state on thedhfr promoter. In support of this notion, recruitment of GAL4-p130 to a dihydrofolate reductase-GAL4 reporter rendered the promoter insensitive to TSA, while repression by GAL4-pRb was sensitive to TSA. Upon phosphorylation of pRb and p130 after serum stimulation, the Sp1-pRb and p130-E2F interactions were lost while the Sp1-HDAC1 interaction persisted into S phase. Together these studies suggest a dynamic model for the cooperation of pRb and p130 in repression ofdhfr gene expression during withdrawal from the cell cycle. We propose that, during initial phases of cell cycle withdrawal, the binding of dephosphorylated pRb to Sp1-HDAC1 complexes and complexes of E2F-1 -to -3 with DP results in transient, HDAC-dependent suppression of dhfr transcription. Upon withdrawal of cells into G0, recruitment of p130 to E2F-4–DP-1 complexes at the transcription start site results in a TSA-insensitive complex that cooperates with Sp1-HDAC-pRb complexes to stably repressdhfr promoter activity in quiescent cells.

scholarly journals Characterization of the human proline/arginine-rich end leucine-rich repeat protein (PRELP) gene promoter and identification of a repressor element

1998 ◽  
Vol 336 (1) ◽  
pp. 77-82 ◽  
Author(s):  
Judy GROVER ◽  
Peter J. ROUGHLEY
Keyword(s):  
Gene Expression ◽  
Binding Site ◽  
Transcription Start Site ◽  
Gene Promoter ◽  
Start Site ◽  
Leucine Rich Repeat ◽  
Transcription Start ◽  
Repeat Protein ◽  
Repressor Element ◽  
Leucine Rich Repeat Protein

The 5´-flanking region of the human proline/arginine-rich end leucine-rich repeat protein (PRELP) gene has been characterized for both promoter and repressor activity by using a variety of reporter gene constructs and transient transfection into chondrocytes or fibroblasts. The human PRELP gene lacks a TATA box, and in its absence a Sp1-binding site residing 29 bp upstream of the transcription start site is essential for initiating gene expression. In contrast, an Ets-binding site residing 497 bp upstream of the transcription start site can lead to the repression of gene expression. The analysis of nuclear proteins by gel retardation studies with the repressor element identified a common protein, presumably an Ets family member, present in neonatal chondrocytes and skin fibroblasts that do not express the PRELP gene. The factor was not detected in nuclear protein preparations from adult chondrocytes in which the PRELP gene is expressed.

scholarly journals Functional analysis of the human annexin I and VI gene promoters

1998 ◽  
Vol 332 (3) ◽  
pp. 681-687 ◽  
Author(s):  
Shaun R. DONNELLY ◽  
Stephen E. MOSS
Keyword(s):  
Gene Expression ◽  
Transcription Start Site ◽  
Luciferase Reporter ◽  
Gene Promoters ◽  
Start Site ◽  
Luciferase Reporter Gene ◽  
Transcription Start ◽  
A431 Cells ◽  
Annexin I ◽  
Annexin Vi

To gain insight into the molecular basis of annexin gene expression we have analysed the annexin I and VI gene promoters. A previously described 881 bp sequence immediately upstream of the annexin I transcription start site and a similar size fragment proximal to the annexin VI transcription start site both drove expression of the luciferase reporter gene in fibroblasts and epithelial cells. Neither promoter displayed any sensitivity to dexamethasone, suggesting that the putative glucocorticoid response element in the annexin I promoter is non-functional. Consistent with this, endogenous annexin I gene expression was unaffected by dexamethasone at the mRNA and protein levels in A431 cells. A series of 5´ deletions of the two promoters were examined to define the minimal active sequences. For annexin I this corresponded to a sequence approx. 150 bp upstream of the transcription start site that included CAAT and TATA boxes. Unexpectedly, the annexin VI promoter, which also contains CAAT and TATA boxes, was fully active in the absence of these elements, a 53 bp sequence between these boxes and the transcription start site having maximal activity. Electrophoretic mobility-shift assays with nuclear extracts from A431 and HeLa cells with probes corresponding to this region revealed an SP1-binding site. These results show that the annexin I and VI genes have individual modes of transcriptional regulation and that if either annexin I or annexin VI has an anti-inflammatory role, then this is in the absence of steroid-induced gene expression.

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