scholarly journals Archaeal transcription factors and their role in transcription initiation

1996 ◽  
Vol 18 (2-3) ◽  
pp. 159-171 ◽  
Author(s):  
Michael Thomm
Genetics ◽  
1999 ◽  
Vol 152 (4) ◽  
pp. 1325-1333
Author(s):  
Carina Hethke ◽  
Agnes Bergerat ◽  
Winfried Hausner ◽  
Patrick Forterre ◽  
Michael Thomm

Abstract Cell-free transcription of archaeal promoters is mediated by two archaeal transcription factors, aTBP and TFB, which are orthologues of the eukaryotic transcription factors TBP and TFIIB. Using the cell-free transcription system described for the hyperthermophilic Archaeon Pyrococcus furiosus by Hethke et al., the temperature limits and template topology requirements of archaeal transcription were investigated. aTBP activity was not affected after incubation for 1 hr at 100°. In contrast, the half-life of RNA polymerase activity was 23 min and that of TFB activity was 3 min. The half-life of a 328-nt RNA product was 10 min at 100°. Best stability of RNA was observed at pH 6, at 400 mm K-glutamate in the absence of Mg2+ ions. Physiological concentrations of K-glutamate were found to stabilize protein components in addition, indicating that salt is an important extrinsic factor contributing to thermostability. Both RNA and proteins were stabilized by the osmolyte betaine at a concentration of 1 m. The highest activity for RNA synthesis at 95° was obtained in the presence of 1 m betaine and 400 mm K-glutamate. Positively supercoiled DNA, which was found to exist in Pyrococcus cells, can be transcribed in vitro both at 70° and 90°. However, negatively supercoiled DNA was the preferred template at all temperatures tested. Analyses of transcripts from plasmid topoisomers harboring the glutamate dehydrogenase promoter and of transcription reactions conducted in the presence of reverse gyrase indicate that positive supercoiling of DNA inhibits transcription from this promoter.


2021 ◽  
Vol 90 (1) ◽  
pp. 193-219
Author(s):  
Emmanuel Compe ◽  
Jean-Marc Egly

In eukaryotes, transcription of protein-coding genes requires the assembly at core promoters of a large preinitiation machinery containing RNA polymerase II (RNAPII) and general transcription factors (GTFs). Transcription is potentiated by regulatory elements called enhancers, which are recognized by specific DNA-binding transcription factors that recruit cofactors and convey, following chromatin remodeling, the activating cues to the preinitiation complex. This review summarizes nearly five decades of work on transcription initiation by describing the sequential recruitment of diverse molecular players including the GTFs, the Mediator complex, and DNA repair factors that support RNAPII to enable RNA synthesis. The elucidation of the transcription initiation mechanism has greatly benefited from the study of altered transcription components associated with human diseases that could be considered transcription syndromes.


1993 ◽  
Vol 13 (7) ◽  
pp. 3860-3871
Author(s):  
P L Sawaya ◽  
B R Stripp ◽  
J A Whitsett ◽  
D S Luse

We have shown that a large fragment (-2339 to +57) from the rat CC10 gene directed lung-specific expression of a reporter construct in transgenic animals. Upon transfection, a smaller fragment (-165 to +57) supported reporter gene expression exclusively in the Clara cell-like NCI-H441 cell line, suggesting that a Clara cell-specific transcriptional element resided on this fragment (B. R. Stripp, P. L. Sawaya, D. S. Luse, K. A. Wikenheiser, S. E. Wert, J. A. Huffman, D. L. Lattier, G. Singh, S. L. Katyal, and J. A. Whitsett, J. Biol. Chem. 267:14703-14712, 1992). The interactions of nuclear proteins with a particular segment of the CC10 promoter which extends from 79 to 128 bp upstream of the CC10 transcription initiation site (CC10 region I) have now been studied. This sequence can stimulate both in vitro transcription in H441 nuclear extract and transient expression of reporter constructs in H441 cells. Electrophoretic mobility shift assays using extracts from H441, HeLa, rat liver, and fetal sheep lung cells were used to demonstrate that members of the AP-1, octamer, and HNF-3 families bind to CC10 region I. Transcription factors from H441 cells which are capable of binding to CC10 region I are either absent in HeLa, rat liver, and fetal sheep lung extracts or enriched in H441 extracts relative to extracts from non-Clara cells.


1997 ◽  
Vol 110 (15) ◽  
pp. 1781-1791 ◽  
Author(s):  
M.A. Grande ◽  
I. van der Kraan ◽  
L. de Jong ◽  
R. van Driel

We have investigated the spatial relationship between sites containing newly synthesized RNA and domains containing proteins involved in transcription, such as RNA polymerase II and the transcription factors TFIIH, Oct1, BRG1, E2F-1 and glucocorticoid receptors, using dual immunofluorescence labelling followed by confocal microscopy on cultured cells. As expected, a high degree of colocalisation between the RNA polymerase II and sites containing newly synthesised RNA was observed. Like the newly synthesised RNA and the RNA polymerase II, we found that all the transcription factors that we studied are distributed more or less homogeneously throughout the nucleoplasm, occupying numerous small domains. In addition to these small domains, TFIIH was found concentrated in coiled bodies and Oct1 in a single large domain of about 1.5 microm in 30% of the cells in an asynchronous HeLa cell culture. Remarkably, we found little or no relationship between the spatial distribution of the glucocorticoid receptor, Oct1 and E2F-1 on the one hand and RNA polymerase II and transcription sites on the other hand. In contrast, a significant but incomplete overlap was observed between the spatial distributions of transcription sites and BRG1 and TFIIH. These results indicate that many of the transcription factor-rich nuclear domains are not actively involved in transcription. They may represent incomplete transcription initiation complexes, inhibitory complexes, or storage sites.


2018 ◽  
Vol 200 (7) ◽  
Author(s):  
Jeong-A Kim ◽  
Mi-Ae Lee ◽  
You-Chul Jung ◽  
Bo-Ram Jang ◽  
Kyu-Ho Lee

ABSTRACTSepticemia-causingVibrio vulnificusproduces at least three exoproteases, VvpE, VvpS, and VvpM, all of which participate in interactions with human cells. Expression of VvpE and VvpS is induced in the stationary phase by multiple transcription factors, including sigma factor S, SmcR, and the cAMP-cAMP receptor protein (cAMP-CRP) complex. Distinct roles of VvpM, such as induction of apoptosis, lead us to hypothesize VvpM expression is different from that of the other exoproteases. Its transcription, which was found to be independent of sigma S, is induced at the early exponential phase and then becomes negligible upon entry into the stationary phase. SmcR and CRP were studied regarding the control ofvvpMexpression. Transcription ofvvpMwas repressed by SmcR and cAMP-CRP complex individually, which specifically bound to the regions −2 to +20 and +6 to +27, respectively, relative to thevvpMtranscription initiation site. Derepression ofvvpMgene expression was 10- to 40-fold greater in ansmcR crpdouble mutant than in single-gene mutants. Therefore, these results show that the expression ofV. vulnificusexoproteases is differentially regulated, and in this way, distinct proteases can engage in specific interactions with a host.IMPORTANCEAn opportunistic human pathogen,Vibrio vulnificusproduces multiple extracellular proteases that are involved in diverse interactions with a host. The total exoproteolytic activity is detected mainly in the supernatants of the high-cell-density cultures. However, some proteolytic activity derived from a metalloprotease, VvpM, was present in the supernatants of the low-cell-density cultures sampled at the early growth period. In this study, we present the regulatory mechanism for VvpM expression via repression by at least two transcription factors. This type of transcriptional regulation is the exact opposite of those for expression of the otherV. vulnificusexoproteases. Differential regulation of each exoprotease's production then facilitates the pathogen's participation in the distinct interactions with a host.


1994 ◽  
Vol 14 (1) ◽  
pp. 373-381 ◽  
Author(s):  
D E Zhang ◽  
C J Hetherington ◽  
H M Chen ◽  
D G Tenen

The macrophage colony-stimulating factor (M-CSF) receptor is expressed in a tissue-specific fashion from two distinct promoters in monocytes/macrophages and the placenta. In order to further understand the transcription factors which play a role in the commitment of multipotential progenitors to the monocyte/macrophage lineage, we have initiated an investigation of the factors which activate the M-CSF receptor very early during the monocyte differentiation process. Here we demonstrate that the human monocytic M-CSF receptor promoter directs reporter gene activity in a tissue-specific fashion. Since one of the few transcription factors which have been implicated in the regulation of monocyte genes is the macrophage- and B-cell-specific PU.1 transcription factor, we investigated whether PU.1 binds and activates the M-CSF receptor promoter. Here we demonstrate that both in vitro-translated PU.1 and PU.1 from nuclear extracts bind to a specific site in the M-CSF receptor promoter just upstream from the major transcription initiation site. Mutations in this site which eliminate PU.1 binding decrease M-CSF receptor promoter activity significantly in macrophage cell lines only. Furthermore, PU.1 transactivates the M-CSF receptor promoter in nonmacrophage cells. These results suggest that PU.1 plays a major role in macrophage gene regulation and development by directing the expression of a receptor for a key macrophage growth factor.


2004 ◽  
Vol 82 (4) ◽  
pp. 453-459 ◽  
Author(s):  
Alexandre M Erkine

Activation domains of promoter-specific transcription factors are critical entities involved in recruitment of multiple protein complexes to gene promoters. The activation domains often retain functionality when transferred between very diverse eukaryotic phyla, yet the amino acid sequences of activation domains do not bear any specific consensus or secondary structure. Activation domains function in the context of chromatin structure and are critical for chromatin remodeling, which is associated with transcription initiation. The mechanisms of direct and indirect recruitment of chromatin-remodeling and histone-modifying complexes, including mechanisms involving direct interactions between activation domains and histones, are discussed.Key words: activation domain, transcription, chromatin, nucleosome.


1999 ◽  
Vol 19 (3) ◽  
pp. 2130-2141 ◽  
Author(s):  
T. C. Kuhlman ◽  
H. Cho ◽  
D. Reinberg ◽  
N. Hernandez

ABSTRACT RNA polymerase II transcribes the mRNA-encoding genes and the majority of the small nuclear RNA (snRNA) genes. The formation of a minimal functional transcription initiation complex on a TATA-box-containing mRNA promoter has been well characterized and involves the ordered assembly of a number of general transcription factors (GTFs), all of which have been either cloned or purified to near homogeneity. In the human RNA polymerase II snRNA promoters, a single element, the proximal sequence element (PSE), is sufficient to direct basal levels of transcription in vitro. The PSE is recognized by the basal transcription complex SNAPc. SNAPc, which is not required for transcription from mRNA-type RNA polymerase II promoters such as the adenovirus type 2 major late (Ad2ML) promoter, is thought to recruit TATA binding protein (TBP) and nucleate the assembly of the snRNA transcription initiation complex, but little is known about which GTFs other than TBP are required. Here we show that the GTFs IIA, IIB, IIF, and IIE are required for efficient RNA polymerase II transcription from snRNA promoters. Thus, although the factors that recognize the core elements of RNA polymerase II mRNA and snRNA-type promoters differ, they mediate the recruitment of many common GTFs.


2004 ◽  
Vol 186 (22) ◽  
pp. 7745-7753 ◽  
Author(s):  
Alexandra Kessler ◽  
Arie B. Brinkman ◽  
John van der Oost ◽  
David Prangishvili

ABSTRACT The double-stranded DNA genomes of the crenarchaeal rudiviruses SIRV1 (32 kb) and SIRV2 (35 kb) were previously sequenced. Here we present results of the analysis of gene expression of these viruses at different time points after infection of the host cell, Sulfolobus islandicus, and of the mapping of transcriptional start sites. Transcription of both genomes starts simultaneously at multiple sites spread over the total length of the genome and from both strands. The earliest time point when viral transcripts could be detected in cells was 30 min after infection. At this time point all the viral genes, except one, were transcribed. Many genes were clustered and appeared to be transcribed as polycistronic messengers. Although the coat protein-encoding gene was initially also transcribed as a polycistronic messenger, an abundant monocistronic transcript of this gene was detected 2 to 3 h after infection, just before assembly of viral particles. The expression of a single gene, adjacent to the coat protein gene, was upregulated at the late phase of infection, suggesting that it might be involved in specific processing and activation of the coat protein messenger. Start sites of 13 transcripts from the SIRV1 genome have been mapped by primer extension, and promoter sequences have been identified. Similar to host promoters, these viral promoters all contain potential binding sites for the archaeal transcription factors TATA binding protein and transcription factor B. In addition, most of them contain a virus-specific consensus element, suggesting the involvement of alternative transcription factors.


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