scholarly journals Bacteriophage P22 Antitermination boxB Sequence Requirements Are Complex and Overlap with Those of λ

2008 ◽  
Vol 190 (12) ◽  
pp. 4263-4271 ◽  
Author(s):  
Alexis I. Cocozaki ◽  
Ingrid R. Ghattas ◽  
Colin A. Smith
Keyword(s):  
Consensus Sequence ◽  
Point Mutations ◽  
Resonance Structure ◽  
Moderate Activity ◽  
Nuclear Magnetic Resonance Structure ◽  
Bacteriophage P22 ◽  
Base Pairs ◽  
Rna Hairpins ◽  
Transcription Antitermination ◽  
Theories Of Evolution

ABSTRACT Transcription antitermination in phages λ and P22 uses N proteins that bind to similar boxB RNA hairpins in regulated transcripts. In contrast to the λ N-boxB interaction, the P22 N-boxB interaction has not been extensively studied. A nuclear magnetic resonance structure of the P22 N peptide boxBleft complex and limited mutagenesis have been reported but do not reveal a consensus sequence for boxB. We have used a plasmid-based antitermination system to screen boxBs with random loops and to test boxB mutants. We find that P22 N requires boxB to have a GNRA-like loop with no simple requirements on the remaining sequences in the loop or stem. U:A or A:U base pairs are strongly preferred adjacent to the loop and appear to modulate N binding in cooperation with the loop and distal stem. A few GNRA-like hexaloops have moderate activity. Some boxB mutants bind P22 and λ N, indicating that the requirements imposed on boxB by P22 N overlap those imposed by λ N. Point mutations can dramatically alter boxB specificity between P22 and λ N. A boxB specific for P22 N can be mutated to λ N specificity by a series of single mutations via a bifunctional intermediate, as predicted by neutral theories of evolution.

scholarly journals The ARS consensus sequence is required for chromosomal origin function in Saccharomyces cerevisiae.

1992 ◽  
Vol 12 (10) ◽  
pp. 4305-4313 ◽  
Author(s):  
A M Deshpande ◽  
C S Newlon
Keyword(s):  
Dna Sequences ◽  
Plasmid Stability ◽  
Single Point ◽  
Consensus Sequence ◽  
Point Mutations ◽  
Base Pairs ◽  
Chromosomal Origin ◽  
Chromosomal Copy ◽  
Origin Function ◽  
Derivatives Of

Replication origins have been mapped to positions that coincide, within experimental error (several hundred base pairs), with ARS elements. To determine whether the DNA sequences required for ARS function on plasmids are required for chromosomal origin function, the chromosomal copy of ARS306 was deleted and the chromosomal copy of ARS307 was replaced with mutant derivatives of ARS307 containing single point mutations in domain A within the ARS core consensus sequence. The chromosomal origin function of these derivatives was assayed by two-dimensional agarose gel electrophoresis. Deletion of ARS306 deleted the associated replication origin. The effects on chromosomal origin function of mutations in domain A paralleled their effects on ARS function, as measured by plasmid stability. These results demonstrate that chromosomal origin function is a property of the ARS element itself.

The ARS consensus sequence is required for chromosomal origin function in Saccharomyces cerevisiae

1992 ◽  
Vol 12 (10) ◽  
pp. 4305-4313
Author(s):  
A M Deshpande ◽  
C S Newlon
Keyword(s):  
Dna Sequences ◽  
Plasmid Stability ◽  
Single Point ◽  
Consensus Sequence ◽  
Point Mutations ◽  
Base Pairs ◽  
Chromosomal Origin ◽  
Chromosomal Copy ◽  
Origin Function ◽  
Derivatives Of

Replication origins have been mapped to positions that coincide, within experimental error (several hundred base pairs), with ARS elements. To determine whether the DNA sequences required for ARS function on plasmids are required for chromosomal origin function, the chromosomal copy of ARS306 was deleted and the chromosomal copy of ARS307 was replaced with mutant derivatives of ARS307 containing single point mutations in domain A within the ARS core consensus sequence. The chromosomal origin function of these derivatives was assayed by two-dimensional agarose gel electrophoresis. Deletion of ARS306 deleted the associated replication origin. The effects on chromosomal origin function of mutations in domain A paralleled their effects on ARS function, as measured by plasmid stability. These results demonstrate that chromosomal origin function is a property of the ARS element itself.

Nuclear Magnetic Resonance Structure of d(GCATATGATAG)·d(CTATCATATGC):  A Consensus Sequence for Promoters Recognized by σKRNA Polymerase†,‡

Biochemistry ◽  
1998 ◽  
Vol 37 (34) ◽  
pp. 11745-11761 ◽  
Author(s):  
Marco Tonelli ◽  
Enzio Ragg ◽  
Anna Maria Bianucci ◽  
Krystyna Lesiak ◽  
Thomas L. James
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Consensus Sequence ◽  
Resonance Structure ◽  
Nuclear Magnetic Resonance Structure ◽  
Nuclear Magnetic

The tumor suppressor p53 regulates its own transcription

1993 ◽  
Vol 13 (6) ◽  
pp. 3415-3423
Author(s):  
A Deffie ◽  
H Wu ◽  
V Reinke ◽  
G Lozano
Keyword(s):  
Consensus Sequence ◽  
Point Mutations ◽  
Direct Interaction ◽  
Mutant P53 ◽  
Tumor Suppressor P53 ◽  
Mobility Shift ◽  
Shift Analysis ◽  
Promoter Deletion Analysis ◽  
Protein Dna Interactions ◽  
Responsive Element

The ability of p53 to suppress transformation correlates with its ability to activate transcription. To identify targets of p53 transactivation, we examined the p53 promoter itself. Northern (RNA) analysis and transient transfection experiments showed that p53 transcriptionally regulated itself. A functionally inactive mutant p53 could not regulate the p53 promoter. Deletion analysis of the p53 promoter delineated sequences between +22 and +67 as being critical for regulation. Electrophoretic mobility shift analysis and methylation interference pinpointed the p53 DNA responsive element. When oligomerized in front of a heterologous minimal promoter, this element was regulated by wild-type p53 and not by mutant p53. Point mutations in the DNA element that eliminated protein-DNA interactions also resulted in a nonresponsive p53 promoter. The DNA element in the p53 promoter responsive to p53 regulation is similar to the p53 consensus sequence. However, we have been unable to detect a direct interaction of p53 with its promoter.

The role of RAP1 in the regulation of the MAT alpha locus

1991 ◽  
Vol 11 (2) ◽  
pp. 1069-1079
Author(s):  
D Giesman ◽  
L Best ◽  
K Tatchell
Keyword(s):  
Transcriptional Activation ◽  
Consensus Sequence ◽  
Point Mutations ◽  
Yeast Cells ◽  
Effective Dosage ◽  
Upstream Region ◽  
Yeast Genome ◽  
Temperature Sensitive ◽  
Lacz Gene

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.

GATA and Ets cis-acting sequences mediate megakaryocyte-specific expression

1993 ◽  
Vol 13 (1) ◽  
pp. 668-676
Author(s):  
V Lemarchandel ◽  
J Ghysdael ◽  
V Mignotte ◽  
C Rahuel ◽  
P H Roméo
Keyword(s):  
Binding Site ◽  
Consensus Sequence ◽  
Mrna Level ◽  
Point Mutations ◽  
Specific Gene ◽  
Cell Type Specificity ◽  
Specific Expression ◽  
Platelet Factor ◽  
Cis Acting ◽  
Dna Fragment

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.

scholarly journals Enhancer and promoter elements directing activation and glucocorticoid repression of the alpha 1-fetoprotein gene in hepatocytes.

1988 ◽  
Vol 8 (4) ◽  
pp. 1398-1407 ◽  
Author(s):  
M Guertin ◽  
H LaRue ◽  
D Bernier ◽  
O Wrange ◽  
M Chevrette ◽  
...  
Keyword(s):  
Glucocorticoid Receptor ◽  
Transient Expression ◽  
Promoter Activity ◽  
Gene Activation ◽  
Point Mutations ◽  
Binding Assays ◽  
Recognition Sequence ◽  
Base Pairs ◽  
Receptor Recognition ◽  
Afp Promoter

Mutations were introduced in 7 kilobases of 5'-flanking rat alpha 1-fetoprotein (AFP) genomic DNA, linked to the chloramphenicol acetyltransferase gene. AFP promoter activity and its repression by a glucocorticoid hormone were assessed by stable and transient expression assays. Stable transfection assays were more sensitive and accurate than transient expression assays in a Morris 7777 rat hepatoma recipient (Hepa7.6), selected for its strong AFP repression by dexamethasone. The segment of DNA encompassing a hepatocyte-constitutive chromatin DNase I-hypersensitive site at -3.7 kilobases and a liver developmental stage-specific site at -2.5 kilobases contains interacting enhancer elements sufficient for high AFP promoter activity in Hepa7.6 or HepG2 cells. Deletions and point mutations define an upstream promoter domain of AFP gene activation, operating with at least three distinct promoter-activating elements, PEI at -65 base pairs, PEII at -120 base pairs, and DE at -160 base pairs. PEI and PEII share homologies with albumin promoter sequences, PEII is a near-consensus nuclear factor I recognition sequence, and DE overlaps a glucocorticoid receptor recognition sequence. An element conferring glucocorticoid repression of AFP gene activity is located in the upstream AFP promoter domain. Receptor-binding assays indicate that this element is the glucocorticoid receptor recognition sequence which overlaps with promoter-activating element DE.

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