Tc, an unusual promoter element required for constitutive transcription of the yeast HIS3 gene

1990 ◽  
Vol 10 (9) ◽  
pp. 4447-4455
Author(s):  
S Mahadevan ◽  
K Struhl

Tc is the proximal promoter element required for constitutive his3 transcription that occurs in the absence of the canonical TATA element (TR) and is initiated from the +1 site. The TC element, unlike TR, does not respond to transcriptional stimulation by the GCN4 or GAL4 activator protein. Analysis of deletion, substitution, and point mutations indicates that Tc mapped between nucleotides -54 and -83 and is a sequence-dependent element because it could not be functionally replaced by other DNA sequences. However, in contrast to the behavior of typical promoter elements, it was surprisingly difficult to eliminate Tc function by base pair substitutions. Of 15 derivatives averaging four substitutions in the Tc region and representing 40% of all possible single changes, only 1 inactivated the Tc element. Moreover, the phenotypes of mutant and hybrid elements indicated that inactivation of Tc required multiple changes. The spacing between Tc and the initiation region could be varied over a 30-base-pair range without significantly affecting the level of transcription from the +1 site. From these results, we consider it possible that Tc may not interact with TFIID or some other typical sequence-specific transcription factor, but instead might influence transcription, either directly or indirectly, by its DNA structure.

1990 ◽  
Vol 10 (9) ◽  
pp. 4447-4455 ◽  
Author(s):  
S Mahadevan ◽  
K Struhl

Tc is the proximal promoter element required for constitutive his3 transcription that occurs in the absence of the canonical TATA element (TR) and is initiated from the +1 site. The TC element, unlike TR, does not respond to transcriptional stimulation by the GCN4 or GAL4 activator protein. Analysis of deletion, substitution, and point mutations indicates that Tc mapped between nucleotides -54 and -83 and is a sequence-dependent element because it could not be functionally replaced by other DNA sequences. However, in contrast to the behavior of typical promoter elements, it was surprisingly difficult to eliminate Tc function by base pair substitutions. Of 15 derivatives averaging four substitutions in the Tc region and representing 40% of all possible single changes, only 1 inactivated the Tc element. Moreover, the phenotypes of mutant and hybrid elements indicated that inactivation of Tc required multiple changes. The spacing between Tc and the initiation region could be varied over a 30-base-pair range without significantly affecting the level of transcription from the +1 site. From these results, we consider it possible that Tc may not interact with TFIID or some other typical sequence-specific transcription factor, but instead might influence transcription, either directly or indirectly, by its DNA structure.


Blood ◽  
1998 ◽  
Vol 91 (6) ◽  
pp. 2126-2132 ◽  
Author(s):  
Thamar B. van Dijk ◽  
Eric Caldenhoven ◽  
Jan A.M. Raaijmakers ◽  
Jan-Willem J. Lammers ◽  
Leo Koenderman ◽  
...  

Eosinophil-derived neurotoxin (EDN) found in the granules of human eosinophils is a cationic ribonuclease toxin. Expression of the EDN gene (RNS2) in eosinophils is dependent on proximal promoter sequences in combination with an enhancer located in the first intron. We further define here the active region of the intron using transfections in differentiated eosinophilic HL60 cells. We show that a region containing a tandem PU.I binding site is important for intronic enhancer activity. This region binds multiple forms of transcription factor PU.I as judged by gel-shift analysis and DNA affinity precipitation. Importantly, introducing point mutations in the PU.I site drastically reduces the intronic enhancer activity, showing the importance of PU.I for expression of EDN in cells of the eosinophilic lineage.


Development ◽  
1999 ◽  
Vol 126 (12) ◽  
pp. 2799-2811 ◽  
Author(s):  
P. Vyas ◽  
M.A. McDevitt ◽  
A.B. Cantor ◽  
S.G. Katz ◽  
Y. Fujiwara ◽  
...  

The lineage-restricted transcription factor GATA-1 is required for differentiation of erythroid and megakaryocytic cells. We have localized a 317 base pair cis-acting regulatory element, HS I, associated with a hematopoietic-specific DNase I hypersensitive site, which lies approx. 3.7 kilobases upstream of the murine hematopoietic-specific GATA-1 IE promoter. HS I directs high-level expression of reporter GATA-1/lacZ genes to primitive and definitive erythroid cells and megakaryocytes in transgenic mice. Comparative sequence analysis of HS I between human and mouse shows approx. 63% nucleotide identity with a more conserved core of 169 base pairs (86% identity). This core contains a GATA site separated by 10 base pairs from an E-box motif. The composite motif binds a multi-protein hematopoietic-specific transcription factor complex which includes GATA-1, SCL/tal-1, E2A, Lmo2 and Ldb-1. Point mutations of the GATA site abolishes HS I function, whereas mutation of the E-box motif still allows reporter gene expression in both lineages. Strict dependence of HS I activity on a GATA site implies that assembly of a protein complex containing a GATA-factor, presumably GATA-1 or GATA-2, is critical to activating or maintaining its function. Further dissection of the 317 base pair region demonstrates that, whereas all 317 base pairs are required for expression in megakaryocytes, only the 5′ 62 base pairs are needed for erythroid-specific reporter expression. These findings demonstrate differential lineage requirements for expression within the HS I element.


2020 ◽  
Author(s):  
C Boedeker ◽  
F Leliaert ◽  
Giuseppe Zuccarello

© 2017 Walter de Gruyter GmbH, Berlin/Boston. Chaetomorpha melagonium is a morphologically distinct species of green algae that occurs throughout the North Atlantic, the North Pacific and the Arctic Ocean. In this study, we analyzed the intraspecific genetic diversity among 14 samples of C. melagonium from across the distribution range based on nuclear large subunit ribosomal DNA (LSU rDNA) and rDNA internal transcribed spacer (ITS) DNA sequences. All samples had identical LSU sequences. The ITS sequences had very few mutations that nevertheless divided the specimens into two groups: one included samples from Iceland, Svalbard, Massachusetts and Alaska with identical ITS sequences; members of this group differed in samples from Europe (France, Germany, Scotland, Sweden, and Wales) by three mutations (two point mutations and one five base pair indel). The European specimens had identical ITS sequences with the exception of a single sample from Brittany that differed by one base pair. The maximum ITS sequence divergence within the samples of C. melagonium was less than 0.5%. This low intraspecific variation in the frequently used highly variable ITS region is discussed in the context of past geological and climatic scenarios.


Blood ◽  
1998 ◽  
Vol 91 (6) ◽  
pp. 2126-2132 ◽  
Author(s):  
Thamar B. van Dijk ◽  
Eric Caldenhoven ◽  
Jan A.M. Raaijmakers ◽  
Jan-Willem J. Lammers ◽  
Leo Koenderman ◽  
...  

Abstract Eosinophil-derived neurotoxin (EDN) found in the granules of human eosinophils is a cationic ribonuclease toxin. Expression of the EDN gene (RNS2) in eosinophils is dependent on proximal promoter sequences in combination with an enhancer located in the first intron. We further define here the active region of the intron using transfections in differentiated eosinophilic HL60 cells. We show that a region containing a tandem PU.I binding site is important for intronic enhancer activity. This region binds multiple forms of transcription factor PU.I as judged by gel-shift analysis and DNA affinity precipitation. Importantly, introducing point mutations in the PU.I site drastically reduces the intronic enhancer activity, showing the importance of PU.I for expression of EDN in cells of the eosinophilic lineage.


1985 ◽  
Vol 5 (11) ◽  
pp. 2951-2958 ◽  
Author(s):  
C F Wright ◽  
R S Zitomer

The transcription of the CYC7 gene of Saccharomyces cerevisiae, encoding the iso-2-cytochrome c protein, is controlled by two upstream regulatory elements, a positive element and a negative element. The nature of the DNA sequences in the negative element were investigated in a two-part approach. The first involved the construction of a CYC7-galK fusion gene which placed the coding sequence of the Escherichia coli galactokinase gene under the regulation of the CYC7 upstream sequences. This fusion allowed the quantitation by galactokinase enzyme assays of the effects on gene expression of a variety of previously isolated deletion mutations within the negative site. The results suggested that the negative site contained three related sequences. This hypothesis was tested in the second part of these studies, the selection of point mutations within the region of the negative site which led to increased CYC7 expression. Point mutations were introduced by a technique which induced mutations within a localized region at high efficiency. All but one of the mutations involved more than a single base-pair change. The mutations followed the pattern that multiple base-pair changes occurred in one repeat or single base-pair changes occurred in two repeats, with the exception of one mutant, which had a single base-pair change in one repeat. This pattern of mutations and the base pairs that were altered strongly supported the hypothesis that the repeats are integral elements of the negative site.


2020 ◽  
Author(s):  
C Boedeker ◽  
F Leliaert ◽  
Giuseppe Zuccarello

© 2017 Walter de Gruyter GmbH, Berlin/Boston. Chaetomorpha melagonium is a morphologically distinct species of green algae that occurs throughout the North Atlantic, the North Pacific and the Arctic Ocean. In this study, we analyzed the intraspecific genetic diversity among 14 samples of C. melagonium from across the distribution range based on nuclear large subunit ribosomal DNA (LSU rDNA) and rDNA internal transcribed spacer (ITS) DNA sequences. All samples had identical LSU sequences. The ITS sequences had very few mutations that nevertheless divided the specimens into two groups: one included samples from Iceland, Svalbard, Massachusetts and Alaska with identical ITS sequences; members of this group differed in samples from Europe (France, Germany, Scotland, Sweden, and Wales) by three mutations (two point mutations and one five base pair indel). The European specimens had identical ITS sequences with the exception of a single sample from Brittany that differed by one base pair. The maximum ITS sequence divergence within the samples of C. melagonium was less than 0.5%. This low intraspecific variation in the frequently used highly variable ITS region is discussed in the context of past geological and climatic scenarios.


2009 ◽  
Vol 23 (7) ◽  
pp. 1001-1013 ◽  
Author(s):  
Pankaj Lamba ◽  
Jérôme Fortin ◽  
Stella Tran ◽  
Ying Wang ◽  
Daniel J. Bernard

Abstract Selective synthesis and release of FSH from pituitary gonadotropes is regulated by activins. Activins directly stimulate murine FSHβ (Fshb) subunit gene transcription through a consensus 8-bp Sma- and Mad-related protein-binding element (SBE) in the proximal promoter. In contrast, the human FSHB promoter is relatively insensitive to the direct effects of activins and lacks this SBE. The proximal porcine Fshb promoter, which is highly conserved with human, similarly lacks the 8-bp SBE, but is nonetheless highly sensitive to activins. We used a comparative approach to determine mechanisms mediating differential activin induction of human, porcine, and murine Fshb/FSHB promoters. We mapped an activin response element in the proximal porcine promoter and identified interspecies variation in a single base pair in close proximity that conferred strong binding of the forkhead transcription factor FOXL2 to the porcine, but not human or murine, promoters. Introduction of the human base pair into the porcine promoter abolished FOXL2 binding and activin A induction. FOXL2 conferred activin A induction to the porcine promoter in heterologous cells, whereas knockdown of the endogenous protein in gonadotropes inhibited the activin A response. The murine Fshb promoter lacks the high-affinity FOXL2-binding site, but its activin induction is FOXL2 sensitive. We identified a more proximal FOXL2-binding element in the murine promoter, which is conserved across species. Mutation of this site attenuated activin A induction of both the porcine and murine promoters. Collectively, the data indicate a novel role for FOXL2 in activin A-regulated Fshb transcription.


1985 ◽  
Vol 5 (11) ◽  
pp. 2951-2958
Author(s):  
C F Wright ◽  
R S Zitomer

The transcription of the CYC7 gene of Saccharomyces cerevisiae, encoding the iso-2-cytochrome c protein, is controlled by two upstream regulatory elements, a positive element and a negative element. The nature of the DNA sequences in the negative element were investigated in a two-part approach. The first involved the construction of a CYC7-galK fusion gene which placed the coding sequence of the Escherichia coli galactokinase gene under the regulation of the CYC7 upstream sequences. This fusion allowed the quantitation by galactokinase enzyme assays of the effects on gene expression of a variety of previously isolated deletion mutations within the negative site. The results suggested that the negative site contained three related sequences. This hypothesis was tested in the second part of these studies, the selection of point mutations within the region of the negative site which led to increased CYC7 expression. Point mutations were introduced by a technique which induced mutations within a localized region at high efficiency. All but one of the mutations involved more than a single base-pair change. The mutations followed the pattern that multiple base-pair changes occurred in one repeat or single base-pair changes occurred in two repeats, with the exception of one mutant, which had a single base-pair change in one repeat. This pattern of mutations and the base pairs that were altered strongly supported the hypothesis that the repeats are integral elements of the negative site.


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