scholarly journals Identification of Aspergillus brlA response elements (BREs) by genetic selection in yeast.

Genetics ◽  
1993 ◽  
Vol 133 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Y C Chang ◽  
W E Timberlake

Abstract The brlA gene of Aspergillus nidulans plays a central role in controlling conidiophore development. To test the hypothesis that brlA encodes a transcriptional regulator and to identify sites of interaction for the BrlA polypeptide, we expressed brlA in Saccharomyces cerevisiae (yeast) strains containing Aspergillus DNA sequences inserted upstream of a minimal yeast promoter fused to the Escherichia coli lacZ gene. Initially, a DNA fragment from the promoter region of the developmentally regulated rodA gene was tested and shown to mediate brlA-dependent transcriptional activation. Two additional DNA fragments were selected from an Aspergillus genomic library by their ability to respond to brlA in yeast. These fragments contained multiple copies of a sequence motif present in the rodA fragment, which we propose to be sites for BrlA interaction and designate brlA response elements (BREs). DNA fragments containing BREs upstream of a minimal Aspergillus promoter were capable of conferring developmental regulation in Aspergillus. Deletion of BREs from the upstream region of rodA greatly decreased its developmental induction. Multiple copies of a synthetic oligonucleotide with the consensus sequence identified among the BREs mediated brlA-dependent transcriptional activation in yeast. The results show that a primary activity of brlA is transcriptional activation and tentatively identify sites of interaction for the BrlA polypeptide.

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.


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.


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.


1996 ◽  
Vol 199 (3) ◽  
pp. 513-520 ◽  
Author(s):  
M Maeda ◽  
K Kubo ◽  
T Nishi ◽  
M Futai

The gastric H+/K(+)-ATPase is a P-type ATPase that is specifically expressed in gastric parietal cells and is responsible for acid secretion into the stomach. We have found one or more gastric mucosal nuclear proteins that recognize a sequence motif in the 5'-upstream regions of the H+/K(+)-ATPase alpha- and beta-subunit genes. This gastric motif, (G/C)PuPu(G/C)NGAT(A/T)PuPy, may be a binding site for a positive transcriptional regulator that functions specifically in parietal cells. We further demonstrated using cDNA cloning and in situ hybridization that novel zinc-finger proteins (GATA-GT1 and GATA-GT2) are present in the gastric parietal cells and bind to this motif. The proteins activate the transcription of the reporter gene with the 5'-upstream region of the H+/K(+)-ATPase beta-subunit gene. These results suggest that gastric GATA DNA-binding proteins have important roles in transcriptional activation of H+/K(+)-ATPase genes in the parietal cells.


1990 ◽  
Vol 10 (5) ◽  
pp. 2285-2293 ◽  
Author(s):  
C E Ibanez ◽  
J S Lipsick

The v-myb oncogene causes acute myelomonocytic leukemia in chickens and transforms avian myeloid cells in vitro. Its product, p48v-myb, is a short-lived nuclear protein which binds DNA. We demonstrate that p48v-myb can function as a trans activator of gene expression in transient DNA transfection assays. trans activation requires the highly conserved amino-terminal DNA-binding domain and the less highly conserved carboxyl-terminal domain of p48v-myb, both of which are required for transformation. Multiple copies of a consensus sequence for DNA binding by p48v-myb inserted upstream of a herpes simplex virus thymidine kinase promoter are strongly stimulatory for transcriptional activation by a v-myb-VP16 fusion protein but not by p48v-myb itself, suggesting that the binding of p48v-myb to DNA may not be sufficient for trans activation.


2007 ◽  
Vol 20 (7) ◽  
pp. 867-881 ◽  
Author(s):  
Monika Janczarek ◽  
Anna Skorupska

The acidic exopolysaccharide is required for the establishment of symbiosis between the nitrogen-fixing bacterium Rhizobium leguminosarum bv. trifolii and clover. Here, we describe RosR protein from R. leguminosarum bv. trifolii 24.2, a homolog of transcriptional regulators belonging to the family of Ros/MucR proteins. R. leguminosarum bv. trifolii RosR possesses a characteristic Cys2His2 type zincfinger motif in its C-terminal domain. Recombinant (His)6RosR binds to an RosR-box sequence located upstream of rosR. Deletion analysis of the rosR upstream region resulted in identification of two -35 to -10 promoter sequences, two conserved inverted palindromic pentamers that resemble the cAMP-CRP binding site of Escherichia coli, inverted repeats identified as a RosR binding site, and other regulatory sequence motifs. When assayed in E. coli, a transcriptional fusion of the cAMP-CRP binding site containing the rosR upstream region and lacZ gene was moderately responsive to glucose. The sensitivity of the rosR promoter to glucose was not observed in E. coli ΔcyaA. A rosR frame-shift mutant of R. leguminosarum bv. trifolii formed dry, wrinkled colonies and induced nodules on clover, but did not fix nitrogen. In the rosR mutant, transcription of pssA-lacZ fusion was decreased, indicating positive regulation of the pssA gene by RosR. Multiple copies of rosR in R. leguminosarum bv. trifolii 24.2 increased exopolysaccharide production.


1990 ◽  
Vol 10 (5) ◽  
pp. 2285-2293 ◽  
Author(s):  
C E Ibanez ◽  
J S Lipsick

The v-myb oncogene causes acute myelomonocytic leukemia in chickens and transforms avian myeloid cells in vitro. Its product, p48v-myb, is a short-lived nuclear protein which binds DNA. We demonstrate that p48v-myb can function as a trans activator of gene expression in transient DNA transfection assays. trans activation requires the highly conserved amino-terminal DNA-binding domain and the less highly conserved carboxyl-terminal domain of p48v-myb, both of which are required for transformation. Multiple copies of a consensus sequence for DNA binding by p48v-myb inserted upstream of a herpes simplex virus thymidine kinase promoter are strongly stimulatory for transcriptional activation by a v-myb-VP16 fusion protein but not by p48v-myb itself, suggesting that the binding of p48v-myb to DNA may not be sufficient for trans activation.


1986 ◽  
Vol 6 (12) ◽  
pp. 4281-4294 ◽  
Author(s):  
D W Russell ◽  
R Jensen ◽  
M J Zoller ◽  
J Burke ◽  
B Errede ◽  
...  

The HO gene product of Saccharomyces cerevisiae is a site-specific endonuclease that initiates mating type interconversion. We have determined the nucleotide sequence of a 3,129-base-pair (bp) segment containing HO. The segment contains a single long open reading frame encoding a polypeptide of 586 amino acids, which has unusual (unbiased) codon usage and is preceded by 762 bp of upstream region. The predicted HO protein is basic (16% lysine and arginine) and is calculated to have a secondary structure that is 30% helical. The corresponding transcript is initiated approximately 50 nucleotides prior to the presumed initiation codon. Insertion of an Escherichia coli lacZ gene fragment into the putative HO coding segment inactivated HO and formed a hybrid HO-lacZ gene whose beta-galactosidase activity was regulated by the mating type locus in the same manner as HO (repressed by a 1-alpha 2). Upstream regions of 1,360 and 762 bp conferred strong repression; 436 bp led to partial constitutivity and 301 bp to full constitutivity. Thus, DNA sequences that confer repression of HO by a1-alpha 2 are at least 250 nucleotides upstream of the transcription start point and are within 436 nucleotides of the HO initiation codon. The progressive loss of repression suggests that both the -762 to -436 and the -436 to -301 intervals contain sites for regulation by a1-alpha 2. The HO gene contains two distinct regions that promote autonomous replication of plasmids in S. cerevisiae. These regions contain sequences that are homologous to the two conserved sequences that are associated with ARS activity.


1986 ◽  
Vol 6 (12) ◽  
pp. 4281-4294
Author(s):  
D W Russell ◽  
R Jensen ◽  
M J Zoller ◽  
J Burke ◽  
B Errede ◽  
...  

The HO gene product of Saccharomyces cerevisiae is a site-specific endonuclease that initiates mating type interconversion. We have determined the nucleotide sequence of a 3,129-base-pair (bp) segment containing HO. The segment contains a single long open reading frame encoding a polypeptide of 586 amino acids, which has unusual (unbiased) codon usage and is preceded by 762 bp of upstream region. The predicted HO protein is basic (16% lysine and arginine) and is calculated to have a secondary structure that is 30% helical. The corresponding transcript is initiated approximately 50 nucleotides prior to the presumed initiation codon. Insertion of an Escherichia coli lacZ gene fragment into the putative HO coding segment inactivated HO and formed a hybrid HO-lacZ gene whose beta-galactosidase activity was regulated by the mating type locus in the same manner as HO (repressed by a 1-alpha 2). Upstream regions of 1,360 and 762 bp conferred strong repression; 436 bp led to partial constitutivity and 301 bp to full constitutivity. Thus, DNA sequences that confer repression of HO by a1-alpha 2 are at least 250 nucleotides upstream of the transcription start point and are within 436 nucleotides of the HO initiation codon. The progressive loss of repression suggests that both the -762 to -436 and the -436 to -301 intervals contain sites for regulation by a1-alpha 2. The HO gene contains two distinct regions that promote autonomous replication of plasmids in S. cerevisiae. These regions contain sequences that are homologous to the two conserved sequences that are associated with ARS activity.


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