scholarly journals SMAD 8 binding to mice Msx1 basal promoter is required for transcriptional activation

2005 ◽  
Vol 393 (1) ◽  
pp. 141-150 ◽  
Author(s):  
Renata Binato ◽  
Cristina E. Alvarez Martinez ◽  
Luciana Pizzatti ◽  
Benoit Robert ◽  
Eliana Abdelhay

The Msx1 gene in mice has been proven to be induced by BMP (bone morphogenetic protein) proteins, and three binding sites for SMAD, an intracellular BMP signalling transducer, have already been identified in its promoter. Gel shift analyses were performed and they demonstrated that the consensus found very near the transcription start site, a region designed BP (basal promoter), is functional for binding nuclear proteins from 10.5, 11.5 and 13.5 dpc (days post-coitum) embryos. Notably, this binding occurs only when the SMAD-binding consensus sequence is maintained, suggesting that it is required for the formation of a protein complex over BP. Binding of purified SMAD 1 and SMAD 4 as well as supershift assay with SMAD 1/SMAD 5/SMAD 8 antibody proved that a SMAD protein is present in this complex. Transfection assays in cell cultures with fragments from BP driving the expression of luciferase confirmed that only in the presence of the SMAD consensus site is Msx1 expression activated. A proteomic analysis of the complex components after immunoprecipitation identified several proteins necessary to activate transcription including SMAD 8. Our results suggest that BMP2/BMP4 signalling through SMAD 8 is required for transcriptional activation of the mouse Msx1 gene.

1994 ◽  
Vol 14 (9) ◽  
pp. 5986-5996
Author(s):  
S P Hunger ◽  
R Brown ◽  
M L Cleary

The t(17;19) translocation in acute lymphoblastic leukemias results in creation of E2A-hepatic leukemia factor (HLF) chimeric proteins that contain the DNA-binding and protein dimerization domains of the basic leucine zipper (bZIP) protein HLF fused to a portion of E2A proteins with transcriptional activation properties. An in vitro binding site selection procedure was used to determine DNA sequences preferentially bound by wild-type HLF and chimeric E2A-HLF proteins isolated from various t(17;19)-bearing leukemias. All were found to selectively bind the consensus sequence 5'-GTTACGTAAT-3' with high affinity. Wild-type and chimeric HLF proteins also bound closely related sites identified previously for bZIP proteins of both the proline- and acidic amino acid-rich (PAR) and C/EBP subfamilies; however, E2A-HLF proteins were significantly less tolerant of certain deviations from the HLF consensus binding site. These differences were directly attributable to loss of an HLF ancillary DNA-binding domain in all E2A-HLF chimeras and were further exacerbated by a zipper mutation in one isolate. Both wild-type and chimeric HLF proteins displayed transcriptional activator properties in lymphoid and nonlymphoid cells on reporter genes containing HLF or C/EBP consensus binding sites. But on reporter genes with nonoptimal binding sites, their transcriptional properties diverged and E2A-HLF competitively inhibited activation by wild-type PAR proteins. These findings establish a spectrum of binding site-specific transcriptional properties for E2A-HLF which may preferentially activate expression of select subordinate genes as a homodimer and potentially antagonize expression of others through heteromeric interactions.


1994 ◽  
Vol 14 (9) ◽  
pp. 5986-5996 ◽  
Author(s):  
S P Hunger ◽  
R Brown ◽  
M L Cleary

The t(17;19) translocation in acute lymphoblastic leukemias results in creation of E2A-hepatic leukemia factor (HLF) chimeric proteins that contain the DNA-binding and protein dimerization domains of the basic leucine zipper (bZIP) protein HLF fused to a portion of E2A proteins with transcriptional activation properties. An in vitro binding site selection procedure was used to determine DNA sequences preferentially bound by wild-type HLF and chimeric E2A-HLF proteins isolated from various t(17;19)-bearing leukemias. All were found to selectively bind the consensus sequence 5'-GTTACGTAAT-3' with high affinity. Wild-type and chimeric HLF proteins also bound closely related sites identified previously for bZIP proteins of both the proline- and acidic amino acid-rich (PAR) and C/EBP subfamilies; however, E2A-HLF proteins were significantly less tolerant of certain deviations from the HLF consensus binding site. These differences were directly attributable to loss of an HLF ancillary DNA-binding domain in all E2A-HLF chimeras and were further exacerbated by a zipper mutation in one isolate. Both wild-type and chimeric HLF proteins displayed transcriptional activator properties in lymphoid and nonlymphoid cells on reporter genes containing HLF or C/EBP consensus binding sites. But on reporter genes with nonoptimal binding sites, their transcriptional properties diverged and E2A-HLF competitively inhibited activation by wild-type PAR proteins. These findings establish a spectrum of binding site-specific transcriptional properties for E2A-HLF which may preferentially activate expression of select subordinate genes as a homodimer and potentially antagonize expression of others through heteromeric interactions.


2015 ◽  
Vol 198 (1) ◽  
pp. 178-186 ◽  
Author(s):  
Claudine Baraquet ◽  
Caroline S. Harwood

ABSTRACTThe transcription factor FleQ fromPseudomonas aeruginosaderepresses expression of genes involved in biofilm formation when intracellular levels of the second messenger cyclic diguanosine monophosphate (c-di-GMP) are high. FleQ also activates transcription of flagellar genes, and the expression of these genes is highest at low intracellular c-di-GMP. FleQ thus plays a central role in mediating the transition between planktonic and biofilm lifestyles ofP. aeruginosa. Previous work showed that FleQ controls expression of thepeloperon for Pel exopolysaccharide biosynthesis by converting from a repressor to an activator upon binding c-di-GMP. To explore the activity of FleQ further, we carried out DNase I footprinting at three additional biofilm gene promoters, those ofpsl,cdrAB, and PA2440. The expression ofcdrAB, encoding a cell surface adhesin, was sufficiently responsive to FleQ to allow us to carry outin vivopromoter assays. The results showed that, similarly to our observations with thepeloperon, FleQ switches from a repressor to an activator ofcdrABgene expression in response to c-di-GMP. From the footprinting data, we identified a FleQ DNA binding consensus sequence. A search for this conserved sequence in bacterial genome sequences led to the identification of FleQ binding sites in the promoters of thesiaABCDoperon, important for cell aggregation, and thebdlAgene, important for biofilm dispersal, inP. aeruginosa. We also identified FleQ binding sites upstream oflapA-like adhesin genes in otherPseudomonasspecies.IMPORTANCEThe transcription factor FleQ is widely distributed inPseudomonasspecies. In all species examined, it is a master regulator of flagellar gene expression. It also regulates diverse genes involved in biofilm formation inP. aeruginosawhen intracellular levels of the second messenger c-di-GMP are high. Unlike flagellar genes, biofilm-associated genes are not always easy to recognize in genome sequences. Here, we identified a consensus DNA binding sequence for FleQ. This allowed us to surveyPseudomonasstrains and find new genes that are likely regulated by FleQ and possibly involved in biofilm formation.


2010 ◽  
Vol 192 (6) ◽  
pp. 1596-1606 ◽  
Author(s):  
Paul Himes ◽  
Steven J. McBryant ◽  
Lee Kroos

ABSTRACT Nutrient limitation causes Bacillus subtilis to develop into two different cell types, a mother cell and a spore. SpoIIID is a key regulator of transcription in the mother cell and positively or negatively regulates more than 100 genes, in many cases by binding to the promoter region. SpoIIID was predicted to have a helix-turn-helix motif for sequence-specific DNA binding, and a 10-bp consensus sequence was recognized in binding sites, but some strong binding sites were observed to contain more than one match to the consensus sequence, suggesting that SpoIIID might bind as a dimer or cooperatively as monomers. Here we show that SpoIIID binds with high affinity as a monomer to a single copy of its recognition sequence. Using charge reversal substitutions of residues likely to be exposed on the surface of SpoIIID and assays for transcriptional activation in vivo and for DNA binding in vitro, we identify two regions essential for DNA binding, the putative recognition helix of the predicted helix-turn-helix motif and a basic region near the C terminus. SpoIIID is unusual among prokaryotic DNA-binding proteins with a single helix-turn-helix motif in its ability to bind DNA monomerically with high affinity. We propose that the C-terminal basic region of SpoIIID makes additional contacts with DNA, analogous to the N-terminal arm of eukaryotic homeodomain proteins and the “wings” of winged-helix proteins, but structurally distinct. SpoIIID is highly conserved only among bacteria that form endospores, including several important human pathogens. The need to conserve biosynthetic capacity during endospore formation might have favored the evolution of a small transcription factor capable of high-affinity binding to DNA as a monomer, and this unusual mode of DNA binding could provide a target for drug design.


1993 ◽  
Vol 13 (9) ◽  
pp. 5805-5813 ◽  
Author(s):  
M M Wang ◽  
R Y Tsai ◽  
K A Schrader ◽  
R R Reed

Genes which mediate odorant signal transduction are expressed at high levels in neurons of the olfactory epithelium. The molecular mechanism governing the restricted expression of these genes likely involves tissue-specific DNA binding proteins which coordinately activate transcription through sequence-specific interactions with olfactory promoter regions. We have identified binding sites for the olfactory neuron-specific transcription factor, Olf-1, in the sequences surrounding the transcriptional initiation site of five olfactory neuron-specific genes. The Olf-1 binding sites described define the consensus sequence YTCCCYRGGGAR. In addition, we have identified a second binding site, the U site, in the olfactory cyclic nucleotide gated channel and type III cyclase promoters, which binds factors present in all tissue examined. These experiments support a model in which expression of Olf-1 in the sensory neurons coordinately activates a set of olfactory neuron-specific genes. Furthermore, expression of a subset of these genes may be modulated by additional binding factors.


PLoS ONE ◽  
2009 ◽  
Vol 4 (10) ◽  
pp. e7526 ◽  
Author(s):  
Alfredo Mendoza-Vargas ◽  
Leticia Olvera ◽  
Maricela Olvera ◽  
Ricardo Grande ◽  
Leticia Vega-Alvarado ◽  
...  

Genome ◽  
2009 ◽  
Vol 52 (3) ◽  
pp. 217-221 ◽  
Author(s):  
Xia Shen ◽  
Bruce Walsh ◽  
Jing J. Li ◽  
Hong X. Pang ◽  
Wen J. Wang ◽  
...  

While many studies of cis-elements CArG bound by serum response factor (SRF) are in progress, little is known about the positional distribution of the functional CArG elements around the transcription start site (TSS) of genes that they influence. We use a validated CArG data set to calculate the distance distribution of functional CArG elements around the TSS. Distances between adjacent CArGs were also analyzed. We compare these distributions with those derived using a control set of randomly selected CArGs (that were not experimentally validated for function). Our results show that most functional CArG elements (108 of 152, 71%) exist upstream of the annotated TSS, with copy number increasing as one moves closer to the TSS. Moreover, the average number of the CArG elements in the CArG-containing genes is significantly more than that in the control genes. Our study extends earlier bioinformatic analyses of functional CArG elements and provides an application of comparative sequence data to the identification of transcription factor binding sites.


2018 ◽  
Vol 16 (01) ◽  
pp. 1750029 ◽  
Author(s):  
Vladimir Y. Ovchinnikov ◽  
Denis V. Antonets ◽  
Lyudmila F. Gulyaeva

MicroRNAs (miRNAs) play important roles in the regulation of gene expression at the post-transcriptional level. Many exogenous compounds or xenobiotics may affect microRNA expression. It is a well-established fact that xenobiotics with planar structure like TCDD, benzo(a)pyrene (BP) can bind aryl hydrocarbon receptor (AhR) followed by its nuclear translocation and transcriptional activation of target genes. Another chemically diverse group of xenobiotics including phenobarbital, DDT, can activate the nuclear receptor CAR and in some cases estrogen receptors ESR1 and ESR2. We hypothesized that such chemicals can affect miRNA expression through the activation of AHR, CAR, and ESRs. To prove this statement, we used in silico methods to find DRE, PBEM, ERE potential binding sites for these receptors, respectively. We have predicted AhR, CAR, and ESRs binding sites in 224 rat, 201 mouse, and 232 human promoters of miRNA-coding genes. In addition, we have identified a number of miRNAs with predicted AhR, CAR, and ESRs binding sites that are known as oncogenes and as tumor suppressors. Our results, obtained in silico, open a new strategy for ongoing experimental studies and will contribute to further investigation of epigenetic mechanisms of carcinogenesis.


1991 ◽  
Vol 11 (2) ◽  
pp. 1069-1079
Author(s):  
D Giesman ◽  
L Best ◽  
K Tatchell

The RAP1 gene of Saccharomyces cerevisiae encodes an abundant DNA-binding protein, also known as GRF1, TBA, or TUF, that binds to many sites in the yeast genome in vitro. These sites define a consensus sequence, [sequence: see text], and deletion analyses of genes that contain this sequence have implicated the involvement of RAP1 in numerous cellular processes, including gene activation and repression. The MAT alpha locus, required for determination of the alpha cell type in yeast cells, contains a RAP1 binding site; this site coincides with the MAT alpha upstream activating sequence (UAS) and is necessary for expression of the two genes encoded by the MAT alpha locus, MAT alpha 1 and MAT alpha 2. We show that the MAT alpha UAS is sufficient to activate transcription from a promoterless gene fusion of the yeast CYC1 upstream region and the lacZ gene. Constructs containing only the MAT alpha UAS generated elevated levels of beta-galactosidase activity which were indistinguishable from those of constructs containing the entire MAT alpha intergenic region. Further, the MAT alpha UAS has an intrinsic polarity of transcriptional activation; transcription of CYC1-lacZ was six- to sevenfold higher when the UAS was oriented in the direction normally associated with MAT alpha 2 transcription. Point mutations in the MAT alpha UAS that reduce MAT alpha expression three- to fivefold resulted in a bi-mating phenotype, while a mutation that reduced MAT alpha expression still further resulted in an a-mating phenotype. We isolated plasmids from a high-copy-number yeast library that suppressed the bi-mating defect of point mutations in the MAT alpha UAS, and the most effective dosage suppressor contained the gene encoding RAP1. A temperature-sensitive rap1 mutant bi-mates at the semipermissive temperature. Double mutants at rap1 and mat alpha mate exclusively as a cells, at all temperatures, and do not express detectable levels of MAT alpha RNA. These data provide evidence that the RAP1 gene product functions at the MAT alpha UAS in vivo.


1988 ◽  
Vol 8 (12) ◽  
pp. 5323-5330
Author(s):  
A C Cato ◽  
E Heitlinger ◽  
H Ponta ◽  
L Klein-Hitpass ◽  
G U Ryffel ◽  
...  

The chicken vitellogenin II gene is transcriptionally activated by estrogens. In transient transfection experiments in human T47D cells that contain receptors for various steroids, we showed estradiol, progestin, and androgen responses of a chimeric chicken vitellogenin II construct. This construct consists of DNA sequences from -626 to -590 upstream of the start of transcription of the chicken vitellogenin gene linked to the herpes simplex virus thymidine kinase promoter driving the transcription of the bacterial chloramphenicol acetyltransferase gene. Treatment of the transfected T47D cells with a combination of estradiol and the progestin R5020 led to a superinduction of chloramphenicol acetyltransferase activity, showing a synergistic action of these two steroids. This synergism was not observed upon treatment of the transfected cells with estradiol and the androgen dihydrotestosterone. Using point mutations in the vitellogenin gene fragment, we showed in functional and in in vitro DNase I footprinting assays with a purified progesterone receptor that, for the synergistic action of estradiol and R5020 to occur, the progesterone receptor must be bound to the vitellogenin gene fragment. The progesterone receptor-binding site was localized at -610 to -590, close to the consensus sequence (-626 to -613) for estrogen receptor binding and function. We therefore demonstrate here that two different steroid hormones can be functionally synergistic through the interaction of their corresponding receptors with two different binding sites adjacent to one another.


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