Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Simultaneous resistance to an array of drugs with different cytotoxic activities is a property of Saccharomyces cerevisiae, in which the protein Pdr3p has recently been shown to play a role as a transcriptional regulator. We provide evidence that the yeast PDR3 gene, which encodes a zinc finger transcription factor implicated in certain drug resistance phenomena, is under positive autoregulation by Pdr3p. DNase I footprinting analyses using bacterially expressed Pdr3p showed specific recognition by this protein of at least two upstream activating sequences in the PDR3 promoter. The use of lacZ reporter constructs, a mutational analysis of the upstream activating sequences, as well as band shift experiments enabled the identification of two 5'TC CGCGGA3' sequence motifs in the PDR3 gene as consensus elements for the binding of Pdr3p. Several similar sequence motifs can be found in the promoter of PDR5, a gene encoding an ATP-dependent drug pump whose Pdr3p-induced overexpression is responsible for drug resistance phenomena. Recently one of these sequence elements was shown to be the target of Pdr3p to elevate the level of PDR5 transcription. Finally, we provide evidence in the absence of PDR1 for a PDR3-controlled transcriptional induction of the drug pump by cycloheximide and propose a model for the mechanism governing the transcriptional autoregulation of Pdr3p.
Mol Cell Biol 1995 Aug
PMID:Positive autoregulation of the yeast transcription factor Pdr3p, which is involved in control of drug resistance. 762

The region commonly deleted in DiGeorge syndrome (DGS) has been localized at 22q11.1-q11.2 with the aid of a high resolution banding technique. A 22q11 specific plasmid library was constructed with a microdissection and microcloning method. Dosage analysis proved three of 144 randomly selected microclones to detect hemizygosity in two patients with DGS. Two of the clones were found to contain independent low-copy-number repetitive sequences, all of which were included in the region deleted in the DGS patients. Screening of the cosmid library and subsequent cosmid walking allowed us to obtain two cosmid contigs corresponding to the microclones within the deletion (contig 1 and contig 2), whose order fluorescence in situ hybridization identified as centromere-contig 1-contig 2-telomere on 22q. By direct selection strategy using one of the cosmids of contig 1, a 4.3 kb cDNA was obtained from fetal brain cDNA library. Sequence analysis of the cDNA revealed an open reading frame encoding 552 amino acids which had several characteristics of DNA-binding proteins. The gene, designated LZTR-1, which was transcribed in several essential fetal organs, proved to be hemizygously deleted in seven of eight DGS patients or its variants, but not in one DGS patient and GM00980. Although LZTR-1 does not locate in the shortest region of overlap, several of its structural characteristics identifying it as transcriptional regulator suggest that it plays a crucial role in embryogenesis and that haploinsufficiency of this gene may be partly related to the development of DGS.
Hum Mol Genet 1995 Apr
PMID:Isolation and characterization of a novel gene deleted in DiGeorge syndrome. 763 2

The human gamma-globin gene promoter contains a stage selector element (SSE) responsible for preferential interaction of the promoter with a powerful erythroid-specific enhancer in the fetal developmental stage (S.M. Jane, P.A. Ney, E.F. Vanin, D.L. Gumucio, and A.W. Nienhuis. EMBO J. 11:2691-2699, 1992). The element binds two proteins, the ubiquitous activator Sp1 and a protein previously known as -50 gamma and now named the stage selector protein (SSP). Binding of the second protein correlates with SSE activity in transient-transfection assays. We now report that a de novo binding site for the SSP is created by the -202(C-->G) mutation that causes hereditary persistence of fetal hemoglobin (HPFH). This site functions in an analogous manner to the SSE in hybrid beta-promoter/reporter gene constructs transfected into K562 cells. In contrast, the wild-type -202 sequence, which fails to bind the SSP, is incapable of activating the beta-gene promoter. Both the -50 and -202 HPFH sites for SSP binding overlap a consensus sequence for the transcriptional regulator Sp1. In addition, both sites contain CpG dinucleotides that are contact bases for SSP. Since the gamma promoter is known to be hypomethylated in fetal cells but fully methylated at CpG residues in adult erythroid cells, we examined the effects of this DNA modification on protein binding to the two regions. Gel mobility shift assays with nuclear extract from K562 cells (which contain both Sp1 and SSP) demonstrate preferential binding of SSP to the SSE and HPFH sites under conditions in which probe was limiting. Methylation of the CpG residues reverses this preference only in the SSE site, with a marked increase in the binding of Sp1 at the expense of the SSP. Purified Sp1 binds with 10-fold higher affinity to the methylated than to the nonmethylated -50 probe but with the same affinity to the -202 HPFH probe. The methylation-induced preferential binding of Sp1 to the SSE at the expense of SSP may be part of the mechanism by which the gamma genes are repressed in normal adult erythroid cells. In cells containing the -202 HPFH mutation, the inability of Sp1 to displace SSP in the methylated state may explain the persistence of gamma-promoter activity and gamma-gene expression observed in adults with this mutation.
Mol Cell Biol 1993 Jun
PMID:Methylation-enhanced binding of Sp1 to the stage selector element of the human gamma-globin gene promoter may regulate development specificity of expression. 768 93

It was recently shown that the E2F-pRB complex is a negative transcriptional regulator. However, it was not determined whether the whole complex or pRB alone is required for repression. Here we show that pRB and the related protein p107 are capable of direct transcriptional repression independent of E2F. When fused to the DNA binding domain of GAL4, pRB or p107 represses transcription of promoters with GAL4 binding sites. Thus, E2F acts as a tether for pRB or p107 but is not actively involved in repression of other enhancers. This function of pRB maps to the pocket and is abrogated by mutation of this domain. This result suggests an intriguing model in which the pocket has a dual function, first to bind E2F and second to repress transcription directly, possibly through interaction with other proteins. We also show that direct transcriptional repression by pRB is regulated by phosphorylation. Mutations which render pRB constitutively hypophosphorylated potentiate repression, while phosphorylation induced by cyclin A or E reduces repression ninefold.
Mol Cell Biol 1995 Jun
PMID:Direct transcriptional repression by pRB and its reversal by specific cyclins. 776 Aug 21

The alcohol dehydrogenase 2 (ADH2) gene of Saccharomyces cerevisiae is under stringent glucose repression. Two cis-acting upstream activation sequences (UAS) that function synergistically in the derepression of ADH2 gene expression have been identified. UAS1 is the binding site for the transcriptional regulator Adr1p. UAS2 has been shown to be important for ADH2 expression and confers glucose-regulated, ADR1-independent activity to a heterologous reporter gene. An analysis of point mutations within UAS2, in the context of the entire ADH2 upstream regulatory region, showed that the specific sequence of UAS2 is important for efficient derepression of ADH2, as would be expected if UAS2 were the binding site for a transcriptional regulatory protein. In the context of the ADH2 upstream regulatory region, including UAS1, working in concert with the ADH2 basal promoter elements, UAS2-dependent gene activation was dependent on orientation, copy number, and helix phase. Multimerization of UAS2, or its presence in reversed orientation, resulted in a decrease in ADH2 expression. In contrast, UAS2-dependent expression of a reporter gene containing the ADH2 basal promoter and coding sequence was enhanced by multimerization of UAS2 and was independent of UAS2 orientation. The reduced expression caused by multimerization of UAS2 in the native promoter was observed only in the presence of ADR1. Inhibition of UAS2-dependent gene expression by Adr1p was also observed with a UAS2-dependent ADH2 reporter gene. This inhibition increased with ADR1 copy number and required the DNA-binding activity of Adr1p. Specific but low-affinity binding of Adr1p to UAS2 in vitro was demonstrated, suggesting that the inhibition of UAS2-dependent gene expression observed in vivo could be a direct effect due to Adr1p binding to UAS2.
Mol Cell Biol 1995 Jun
PMID:Synergistic activation of ADH2 expression is sensitive to upstream activation sequence 2 (UAS2) orientation, copy number and UAS1-UAS2 helical phasing. 776 Aug 41

The transcriptional regulation of the pilE gene, coding for the pilin in Neisseria gonorrhoeae, by PilA/PilB proteins is quite complex. Sequence analysis of PilA suggested that it has multiple domains. PilA appears to have in its N-terminal half a DNA-binding site followed by a region showing sequence similarity with other bacterial transcriptional regulators. In its C-terminal half, PilA has extensive homology with the 54 kDa protein of the eukaryotic signal-recognition particle which is involved in protein secretion. A transcriptional fusion between the promoter of pilE and the lacZ gene was constructed and integrated into the gonococcal chromosome. We show that transcription of the pilE-lacZ fusion is affected in pilA mutants in the absence of any possible interference with pilin secretion. Moreover, pilE transcription depends on a -24/-12-type promoter which could be a member of a family of promoters recognized by the alternative sigma subunit, RpoN, of the RNA polymerase. We also show that PilA binds specifically to the promoter region of pilE and that it is phosphorylated in a manner dependent on acidic residues Glu-59, Asp-149 and Asp-186. The functional organization of PilA suggests that it may be an unusual transcriptional regulator different from other RpoN-dependent activators.
Mol Microbiol 1995 Feb
PMID:Phosphorylation and functional analysis of PilA, a protein involved in the transcriptional regulation of the pilin gene in Neisseria gonorrhoeae. 778 39

Previous studies have indicated that mutation of RAP1 (rap1s) or of the HMR-E silencer ARS consensus element leads to metastable repression of HMR. A number of extragenic suppressor mutations (sds, suppressors of defective silencing) that increase the fraction of repressed cells in rap1s hmr delta A strains have been identified. Here we report the cloning of three SDS genes. SDS11 is identical to SWI6, a transcriptional regulator of genes required for DNA replication and of cyclin genes. SDS12 is identical to RNR1, which encodes a subunit of ribonucleotide reductase. SDS15 is identical to CIN8, whose product is required for spindle formation. We propose that mutations in these genes improve the establishment of silencing by interfering with normal cell cycle progression. In support of this idea, we show that exposure to hydroxyurea, which increases the length of S phase, also restores silencing in rap1s hmr delta A strains. Mutations in different cyclin genes (CLN3, CLB5, and CLB2) and two cell cycle transcriptional regulators (SWI4 and MBP1) also suppress the silencing defect at HMR. The effect of these cell cycle regulators is not specific to the rap1s or hmr delta A mutation, since swi6, swi4, and clb5 mutations also suppress mutations in SIR1, another gene implicated in the establishment of silencing. Several mutations also improve the efficiency of telomeric silencing in wild-type strains, further demonstrating that disturbance of the cell cycle has a general effect on position effect repression in Saccharomyces cerevisiae. We suggest several possible models to explain this phenomenon.
Mol Cell Biol 1995 Jul
PMID:Disturbance of normal cell cycle progression enhances the establishment of transcriptional silencing in Saccharomyces cerevisiae. 779 68

The Leu3 protein of Saccharomyces cerevisiae has been shown to be a transcriptional regulator of genes encoding enzymes of the branched-chain amino acid biosynthetic pathways. Leu3 binds to upstream activating sequences (UASLEU) found in the promoters of LEU1, LEU2, LEU4, ILV2, and ILV5. In vivo and in vitro studies have shown that activation by Leu3 requires the presence of alpha-isopropylmalate. In at least one case (LEU2), Leu3 actually represses basal-level transcription when alpha-isopropylmalate is absent. Following identification of a UASLEU-homologous sequence in the promoter of GDH1, the gene encoding NADP(+)-dependent glutamate dehydrogenase, we demonstrate that Leu3 specifically interacts with this UASLEU element. We then show that Leu3 is required for full activation of the GDH1 gene. First, the expression of a GDH1-lacZ fusion gene is three- to sixfold lower in a strain lacking the LEU3 gene than in an isogenic LEU3+ strain. Expression is restored to near-normal levels when the leu3 deletion cells are transformed with a LEU3-bearing plasmid. Second, a significant decrease in GDH1-lacZ expression is also seen when the UASLEU of the GDH1-lacZ construct is made nonfunctional by mutation. Third, the steady-state level of GDH1 mRNA decreases about threefold in leu3 null cells. The decrease in GDH1 expression in leu3 null cells is reflected in a diminished specific activity of NADP(+)-dependent glutamate dehydrogenase. We also demonstrate that the level of GDH1-lacZ expression correlates with the cells' ability to generate alpha-isopropylmalate and is lowest in cells unable to produce alpha-isopropylmalate. We conclude that GDH1, which plays an important role in the assimilation of ammonia in yeast cells, is, in part, activated by a Leu3-alpha-isopropylmalate complex. This conclusion suggests that Leu3 participates in transcriptional regulation beyond the branched-chain amino acid biosynthetic pathways.
Mol Cell Biol 1995 Jan
PMID:The Saccharomyces cerevisiae Leu3 protein activates expression of GDH1, a key gene in nitrogen assimilation. 779 61

The ets-1 protein has been primarily studied as a sequence-specific transcriptional regulator that is predominately expressed in lymphoid cells. In this report, we show that ets-1 is also expressed in astrocytes and astrocytoma cells and is regulated during both signal transduction and differentiation. Both isoforms of ets-1, p51 and p42, were found in astrocytes and astrocytoma cells, but whereas expression of p51 was strong, p42, the alternate splice product previously shown to lack the phosphorylation domain, was difficult to detect and was present at a level 10- to 40-fold lower than that of p51. This differed by roughly an order of magnitude from the ratio generally observable in T cells and thymocytes. In two astrocytoma lines of human origin, CCF and 1321N1, ets-1 phosphorylation was stimulated by bradykinin and carbachol, respectively. Glutamate, norepinephrine, and bradykinin elicited phosphorylation of p51 in cultures of primary rat type 1 astrocytes. ets-1 phosphorylation was dramatically blocked by KT5926, an inhibitor of myosin light-chain kinase, suggesting that this kinase may be involved in phosphorylation of ets-1 in vivo. Investigations of retinoic acid-induced differentiation in P19 cells provided further support for a strong correlation of ets-1 with the pathway for astrocyte differentiation.
Mol Cell Biol 1995 Feb
PMID:ets-1 in astrocytes: expression and transmitter-evoked phosphorylation. 782 57

SIN3 was first identified by a mutation which suppresses the effects of an swi5 mutation on expression of the HO gene in Saccharomyces cerevisiae. We now show that a sin3 mutation also partially suppresses the effects of swi1 on HO transcription, and partially suppresses the growth defect and inositol requirement observed in swi1 mutants. This suggests that SIN3 and SWI1 may play opposite regulatory roles in controlling expression of many yeast genes. Yeast SIN3 has been shown to function as a negative transcriptional regulator of a number of yeast genes. However, expression of the yeast STE6 gene is reduced in a sin3 mutant strain. This suggests that SIN3 functions as a positive regulator for STE6 transcription, although this apparent activation function could be indirect. In order to understand how SIN3 functions in STE6 regulation, we have performed a genetic analysis. It has been previously demonstrated that MCM1 and STE12 are transcriptional activators of a-specific genes such as STE6, and we now show that SWI1 is also required for STE6 expression. Our data suggest that STE12 and SWI1 function in different pathways of activation, and that STE12 is epistatic to SIN3 and SWI1. We show that the activities of the Mcm1p and Ste12p activators are modestly reduced in a sin3 mutant strain, and that phosphorylation of the Ste12p activator is decreased in a sin3 mutant. Thus, it is possible that the decreased transcription of STE6 in sin3 mutants is due to the combined effect of the diminished activities of Mcm1p and Ste12p.
Mol Gen Genet 1994 Dec 15
PMID:Genetic interactions between SIN3 mutations and the Saccharomyces cerevisiae transcriptional activators encoded by MCM1, STE12, and SWI1. 783 Jul 15


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