A regulatory element in the CHA1 promoter which confers inducibility by serine and threonine on Saccharomyces cerevisiae genes

1993 ◽  
Vol 13 (12) ◽  
pp. 7604-7611
Author(s):  
C Bornaes ◽  
M W Ignjatovic ◽  
P Schjerling ◽  
M C Kielland-Brandt ◽  
S Holmberg

CHA1 of Saccharomyces cerevisiae is the gene for the catabolic L-serine (L-threonine) dehydratase, which is responsible for biodegradation of serine and threonine. We have previously shown that expression of the CHA1 gene is transcriptionally induced by serine and threonine. Northern (RNA) analysis showed that the additional presence of good nitrogen sources affects induction. This may well be due to inducer exclusion. To identify interactions of cis-acting elements with trans activators of the CHA1 promoter, we performed band shift assays of nuclear protein extracts with CHA1 promoter fragments. By this approach, we identified a protein-binding site of the CHA1 promoter. The footprint of this protein contains the ABF1-binding site consensus sequence. This in vitro binding activity is present irrespectively of CHA1 induction. By deletion analysis, two other elements of the CHA1 promoter, UAS1CHA and UAS2CHA, which are needed for induction of the CHA1 gene were identified. Each of the two sequence elements is sufficient to confer serine and threonine induction upon the CYC1 promoter when substituting its upstream activating sequence. Further, in a cha4 mutant strain which is unable to grow with serine or threonine as the sole nitrogen source, the function of UAS1CHA, as well as that of UAS2CHA, is obstructed.

1993 ◽  
Vol 13 (12) ◽  
pp. 7604-7611 ◽  
Author(s):  
C Bornaes ◽  
M W Ignjatovic ◽  
P Schjerling ◽  
M C Kielland-Brandt ◽  
S Holmberg

CHA1 of Saccharomyces cerevisiae is the gene for the catabolic L-serine (L-threonine) dehydratase, which is responsible for biodegradation of serine and threonine. We have previously shown that expression of the CHA1 gene is transcriptionally induced by serine and threonine. Northern (RNA) analysis showed that the additional presence of good nitrogen sources affects induction. This may well be due to inducer exclusion. To identify interactions of cis-acting elements with trans activators of the CHA1 promoter, we performed band shift assays of nuclear protein extracts with CHA1 promoter fragments. By this approach, we identified a protein-binding site of the CHA1 promoter. The footprint of this protein contains the ABF1-binding site consensus sequence. This in vitro binding activity is present irrespectively of CHA1 induction. By deletion analysis, two other elements of the CHA1 promoter, UAS1CHA and UAS2CHA, which are needed for induction of the CHA1 gene were identified. Each of the two sequence elements is sufficient to confer serine and threonine induction upon the CYC1 promoter when substituting its upstream activating sequence. Further, in a cha4 mutant strain which is unable to grow with serine or threonine as the sole nitrogen source, the function of UAS1CHA, as well as that of UAS2CHA, is obstructed.


1998 ◽  
Vol 180 (16) ◽  
pp. 4080-4088 ◽  
Author(s):  
Shin-Ichi Maeda ◽  
Yuriko Kawaguchi ◽  
Taka-Aki Ohe ◽  
Tatsuo Omata

ABSTRACT There are three binding sites for NtcA (nirI,nirII, and nirIII), the global nitrogen regulator of cyanobacteria, in the DNA region between the two divergently transcribed operons (nirA andnirB operons) involved in nitrate assimilation inSynechococcus sp. strain PCC 7942. Using theluxAB reporter system, we showed that nirI andnirIII, which are located 23 bp upstream from the −10 promoter element of nirA and nirB, respectively, are required for induction by nitrogen depletion of thenirA and nirB operons, respectively. The induction of nirA operon transcription was a prerequisite for the nitrite-responsive positive regulation of the transcription by NtcB, a LysR-type protein. The NtcA-binding sitenirII, located in the middle of the nirA-nirBintergenic region, and a potential binding site for a LysR-type protein (TGCAN5TGCA; designated L1), located betweennirI and nirII, were required for the nitrite-responsive, NtcB-dependent enhancement of nirAoperon transcription. Although the requirement for the L1 site was consistent with the involvement of the LysR family protein NtcB in transcriptional regulation, NtcB did not bind to the nirAregulatory region in vitro in the presence of nitrite and NtcA, suggesting the involvement of some additional factor(s) in the regulation. An L1-like inverted repeat with the consensus sequence TGCN7GCA was conserved in the nirA promoter region of cyanobacteria, being centered at position −23 with respect to the NtcA-binding site corresponding to nirI, which suggested the common occurrence of nitrite-responsive regulation of the nitrate assimilation operon among cyanobacteria.


Genetics ◽  
2000 ◽  
Vol 156 (1) ◽  
pp. 183-194
Author(s):  
Douglas B Rusch ◽  
Thomas C Kaufman

Abstract The gene proboscipedia (pb) is a member of the Antennapedia complex in Drosophila and is required for the proper specification of the adult mouthparts. In the embryo, pb expression serves no known function despite having an accumulation pattern in the mouthpart anlagen that is conserved across several insect orders. We have identified several of the genes necessary to generate this embryonic pattern of expression. These genes can be roughly split into three categories based on their time of action during development. First, prior to the expression of pb, the gap genes are required to specify the domains where pb may be expressed. Second, the initial expression pattern of pb is controlled by the combined action of the genes Deformed (Dfd), Sex combs reduced (Scr), cap'n'collar (cnc), and teashirt (tsh). Lastly, maintenance of this expression pattern later in development is dependent on the action of a subset of the Polycomb group genes. These interactions are mediated in part through a 500-bp regulatory element in the second intron of pb. We further show that Dfd protein binds in vitro to sequences found in this fragment. This is the first clear demonstration of autonomous positive cross-regulation of one Hox gene by another in Drosophila melanogaster and the binding of Dfd to a cis-acting regulatory element indicates that this control might be direct.


1993 ◽  
Vol 13 (11) ◽  
pp. 6866-6875 ◽  
Author(s):  
D C Hagen ◽  
L Bruhn ◽  
C A Westby ◽  
G F Sprague

Transcription activation of alpha-specific genes in Saccharomyces cerevisiae is regulated by two proteins, MCM1 and alpha 1, which bind to DNA sequences, called P'Q elements, found upstream of alpha-specific genes. Neither MCM1 nor alpha 1 alone binds efficiently to P'Q elements. Together, however, they bind cooperatively in a manner that requires both the P' sequence, which is a weak binding site for MCM1, and the Q sequence, which has been postulated to be the binding site for alpha 1. We analyzed a collection of point mutations in the P'Q element of the STE3 gene to determine the importance of individual base pairs for alpha-specific gene transcription. Within the 10-bp conserved Q sequence, mutations at only three positions strongly affected transcription activation in vivo. These same mutations did not affect the weak binding to P'Q displayed by MCM1 alone. In vitro DNA binding assays showed a direct correlation between the ability of the mutant sequences to form ternary P'Q-MCM1-alpha 1 complexes and the degree to which transcription was activated in vivo. Thus, the ability of alpha 1 and MCM1 to bind cooperatively to P'Q elements is critical for activation of alpha-specific genes. In all natural alpha-specific genes the Q sequence is adjacent to the degenerate side of P'. To test the significance of this geometry, we created several novel juxtapositions of P, P', and Q sequences. When the Q sequence was opposite the degenerate side, the composite QP' element was inactive as a promoter element in vivo and unable to form stable ternary QP'-MCM1-alpha 1 complexes in vitro. We also found that addition of a Q sequence to a strong MCM1 binding site allows the addition of alpha 1 to the complex. This finding, together with the observation that Q-element point mutations affected ternary complex formation but not the weak binding of MCM1 alone, supports the idea that the Q sequence serves as a binding site for alpha 1.


1991 ◽  
Vol 11 (2) ◽  
pp. 1048-1061
Author(s):  
I J Lee ◽  
L Tung ◽  
D A Bumcrot ◽  
E S Weinberg

A protein, denoted UHF-1, was found to bind upstream of the transcriptional start site of both the early and late H4 (EH4 and LH4) histone genes of the sea urchin Strongylocentrotus purpuratus. A nuclear extract from hatching blastulae contained proteins that bind to EH4 and LH4 promoter fragments in a band shift assay and produced sharp DNase I footprints upstream of the EH4 gene (from -133 to -106) and the LH4 gene (from -94 to -66). DNase I footprinting performed in the presence of EH4 and LH4 promoter competitor DNAs indicated that UHF-1 binds more strongly to the EH4 site. A sequence match of 11 of 13 nucleotides was found within the two footprinted regions: [sequence: see text]. Methylation interference and footprinting experiments showed that UHF-1 bound to the two sites somewhat differently. DNA-protein UV cross-linking studies indicated that UHF-1 has an electrophoretic mobility on sodium dodecyl sulfate-acrylamide gels of approximately 85 kDa and suggested that additional proteins, specific to each promoter, bind to each site. In vitro and in vivo assays were used to demonstrate that the UHF-1-binding site is essential for maximal transcription of the H4 genes. Deletion of the EH4 footprinted region resulted in a 3-fold decrease in transcription in a nuclear extract and a 2.6-fold decrease in expression in morulae from templates that had been injected into eggs. In the latter case, deletion of the binding site did not grossly disrupt the temporal program of expression from the injected EH4 genes. LH4 templates containing a 10-bp deletion in the consensus region or base substitutions in the footprinted region were transcribed at 14 to 58% of the level of the wild-type LH4 template. UHF-1 is therefore essential for maximal expression of the early and late H4 genes.


1989 ◽  
Vol 9 (10) ◽  
pp. 4204-4212
Author(s):  
M H Feuerman ◽  
R Godbout ◽  
R S Ingram ◽  
S M Tilghman

Previous work identified four upstream cis-acting elements required for tissue-specific expression of the alpha-fetoprotein (AFP) gene: three distal enhancers and a promoter. To further define the role of the promoter in regulating AFP gene expression, segments of the region were tested for the ability to direct transcription of a reporter gene in transient expression assay. Experiments showed that the region within 250 base pairs of the start of transcription was sufficient to confer liver-specific transcription. DNase I footprinting and band shift assays indicated that the region between -130 and -100 was recognized by two factors, one of which was highly sequence specific and found only in hepatoma cells. Competition assays suggested that the liver-specific binding activity was HNF-1, previously identified by its binding to other liver-specific promoters. Mutation of the HNF-1 recognition site at -120 resulted in a significant reduction in transcription in transfection assays, suggesting a biological role for HNF-1 in the regulation of AFP expression.


1993 ◽  
Vol 13 (1) ◽  
pp. 668-676
Author(s):  
V Lemarchandel ◽  
J Ghysdael ◽  
V Mignotte ◽  
C Rahuel ◽  
P H Roméo

The human glycoprotein IIB (GPIIB) gene is expressed only in megakaryocytes, and its promoter displays cell type specificity. We show that this specificity involved two cis-acting sequences. The first one, located at -55, contains a GATA binding site. Point mutations that abolish protein binding on this site decrease the activity of the GPIIB promoter but do not affect its tissue specificity. The second one, located at -40, contains an Ets consensus sequence, and we show that Ets-1 or Ets-2 protein can interact with this -40 GPIIB sequence. Point mutations that impair Ets binding decrease the activity of the GPIIB promoter to the same extent as do mutations that abolish GATA binding. A GPIIB 40-bp DNA fragment containing the GATA and Ets binding sites can confer activity to a heterologous promoter in megakaryocytic cells. This activity is independent of the GPIIB DNA fragment orientation, and mutations on each binding site result in decreased activity. Using cotransfection assays, we show that c-Ets-1 and human GATA1 can transactive the GPIIB promoter in HeLa cells and can act additively. Northern (RNA) blot analysis indicates that the ets-1 mRNA level is increased during megakaryocyte-induced differentiation of erythrocytic/megakaryocytic cell lines. Gel retardation assays show that the same GATA-Ets association is found in the human GPIIB enhancer and the rat platelet factor 4 promoter, the other two characterized regulatory regions of megakaryocyte-specific genes. These results indicate that GATA and Ets cis-acting sequences are an important determinant of megakaryocytic specific gene expression.


1983 ◽  
Vol 3 (4) ◽  
pp. 672-683
Author(s):  
W E Courchesne ◽  
B Magasanik

The activities of the proline-specific permease (PUT4) and the general amino acid permease (GAP1) of Saccharomyces cerevisiae vary 70- to 140-fold in response to the nitrogen source of the growth medium. The PUT4 and GAP1 permease activities are regulated by control of synthesis and control of activity. These permeases are irreversibly inactivated by addition of ammonia or glutamine, lowering the activity to that found during steady-state growth on these nitrogen sources. Mutants altered in the regulation of the PUT4 permease (Per-) have been isolated. The mutations in these strains are pleiotropic and affect many other permeases, but have no direct effect on various cytoplasmic enzymes involved in nitrogen assimilation. In strains having one class of mutations (per1), ammonia inactivation of the PUT4 and GAP1 permeases did not occur, whereas glutamate and glutamine inactivation did. Thus, there appear to be two independent inactivation systems, one responding to ammonia and one responding to glutamate (or a metabolite of glutamate). The mutations were found to be nuclear and recessive. The inactivation systems are constitutive and do not require transport of the effector molecules per se, apparently operating on the inside of the cytoplasmic membrane. The ammonia inactivation was found not to require a functional glutamate dehydrogenase (NADP). These mutants were used to show that ammonia exerts control of arginase synthesis largely by inducer exclusion. This may be the primary mode of nitrogen regulation for most nitrogen-regulated enzymes of S. cerevisiae.


1992 ◽  
Vol 12 (9) ◽  
pp. 4093-4103
Author(s):  
D Falb ◽  
T Maniatis

Expression of the Drosophila melanogaster Adh gene in adults requires a fat body-specific enhancer called the Adh adult enhancer (AAE). We have identified a protein in Drosophila nuclear extracts that binds specifically to a site within the AAE (adult enhancer factor 1 [AEF-1]). In addition, we have shown that AEF-1 binds specifically to two other Drosophila fat body enhancers. Base substitutions in the AEF-1 binding site that disrupt AEF-1 binding in vitro result in a significant increase in the level of Adh expression in vivo. Thus, the AEF-1 binding site is a negative regulatory element within the AAE. A cDNA encoding the AEF-1 protein was isolated and shown to act as a repressor of the AAE in cotransfection studies. The AEF-1 protein contains four zinc fingers and an alanine-rich sequence. The latter motif is found in other eukaryotic proteins known to be transcriptional repressors.


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