scholarly journals Two Regions of Bacillus subtilis Transcription Factor SpoIIID Allow a Monomer To Bind DNA

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.

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.


1997 ◽  
Vol 17 (4) ◽  
pp. 1848-1859 ◽  
Author(s):  
E Dodou ◽  
R Treisman

Mutation of Saccharomyces cerevisiae RLM1, which encodes a MADS-box transcription factor, confers resistance to the toxic effects of constitutive activity of the Mpk1 mitogen-activated kinase (MAPK) pathway. The Rlm1 DNA-binding domain, which is similar to that of the metazoan MEF2 transcription factors, is also closely related to that of a second S. cerevisiae protein, Smp1 (second MEF2-like protein), encoded by the YBR182C open reading frame (N. Demolis et al., Yeast 10:1511-1525, 1994; H. Feldmann et al., EMBO J. 13:5795-5809, 1994). We show that Rlm1 and Smp1 have MEF2-related DNA-binding specificities: Rlm1 binds with the same specificity as MEF2, CTA(T/A)4TAG, while SMP1 binds a more extended consensus sequence, ACTACTA(T/A)4TAG. The two DNA-binding domains can heterodimerize with each other and with MEF2A. Deletion of RLM1 enhances resistance to cell wall disruptants, increases saturation density, reduces flocculation, and inactivates reporter genes controlled by the Rlm1 consensus binding site. Deletion of SMP1 neither causes these phenotypes nor enhances the Rlm1 deletion phenotype. However, overexpression of the DNA-binding domain of either protein causes an osmoremedial phenotype. Synthetic and naturally occurring MEF2 consensus sequences exhibit strong RLM1- and MPK1-dependent upstream activation sequence activity. Transcriptional activation by Rlm1 requires its C-terminal sequences, and Gal4 fusion proteins containing Rlm1 C-terminal sequences also act as MPK1-dependent transcriptional activators. These results establish the Rlm1 C-terminal sequences as a target for the Mpk1 MAPK pathway.


1999 ◽  
Vol 13 (8) ◽  
pp. 1402-1416 ◽  
Author(s):  
Pilar Pena ◽  
Anne T. Reutens ◽  
Chris Albanese ◽  
Mark D’Amico ◽  
Genichi Watanabe ◽  
...  

Abstract The ovine P450 side chain cleavage (CYP11A1) enzyme gene, which catalyzes the initial enzymatic step in steroid hormone biosynthesis is transcriptionally regulated in cultured steroidogenic human trophoblastic JEG-3 cells. The ovine CYP11A1 promoter contains two GC-rich footprinted regions referred to as ovine footprints 5 (OF5) and OF3, which are well conserved among the CYP11A1 promoters of different species. These GC-rich sequences resemble activator protein-2 (AP-2)/Sp1 binding sites and were previously implicated in basal and cAMP-regulated activity of the bovine and ovine CYP11A1 promoters. In the current studies, AP-2 induced the ovine CYP11A1 promoter 4.5-fold in JEG-3 cells with full induction requiring the previously defined cAMP-responsive elements. Point mutation of OF3 abolished induction by AP-2, and OF3 was sufficient for induction by AP-2 when linked to a heterologous promoter. AP-2 induction of the CYP11A1 promoter required the basic region (N165-N278) and the carboxy terminus of AP-2 (N413-N437). In the course of investigating the mechanisms by which OF5 and OF3 regulated CYP11A1 transcription, we found that OF5 and OF3 bound Sp1 and Sp3 in JEG-3 cells. AP-2 did not bind OF5 or OF3 directly but rather formed a multiprotein complex with Sp1 in JEG-3 cells. AP-2 associated directly with Sp1 in vitro requiring the AP-2 basic region and the Sp1 carboxy terminus. AP-2 induced Sp1/Sp3 activity independently of AP-2 binding to DNA using a GAL4 paradigm. The Sp1 and Sp3 transactivation domains were linked to the DNA-binding domain of GAL4, and their activity was assessed using a luciferase reporter gene containing only the GAL4 DNA-binding sites linked to the minimal TATA site. AP-2 induced Sp1/Sp3-GAL4 activity 3- to 4-fold, requiring both the amino and extreme carboxy terminus of AP-2. We conclude that AP-2 can bind to and stimulate Sp1 activity and induces the ovine CYP11A1 promoter through conserved Sp1/Sp3-binding sites in JEG-3 cells. The induction of Sp1 activity by AP-2 may contribute to the induction of other genes that bind Sp1.


1988 ◽  
Vol 8 (11) ◽  
pp. 4598-4607 ◽  
Author(s):  
T Hoey ◽  
R Warrior ◽  
J Manak ◽  
M Levine

The homeo box gene even-skipped (eve) encodes a 376-amino-acid protein that binds with high affinity to sequences located near the 5' termini of the eve and en genes. The 5' en sites are A + T rich and contain copies of the 10-base-pair (bp) consensus sequence T-C-A-A-T-T-A-A-A-T. In contrast, the 5' eve sites are G + C rich and contain the 9-bp sequence T-C-A-G-C-A-C-C-G. Among the five different homeo box proteins that have been tested for binding, eve is unique in that it shows virtually equal preference for the A + T-rich 5' en binding sites and the G + C-rich 5' eve sites. Most of the other proteins bind with a relatively higher affinity to the en sites than to the eve sites. In an effort to identify the regions of the eve protein that are responsible for its efficient binding to both classes of recognition sequences, we analyzed the DNA-binding properties of various mutant eve proteins. These studies suggest that the homeo domain of the eve protein is responsible for both binding activities. However, mutations in distant regions of the protein influenced the binding behavior of the eve homeo domain and caused a reduction in binding to the G + C class of recognition sites. We propose that the protein context of the homeo domain can influence its DNA-binding properties.


1988 ◽  
Vol 8 (11) ◽  
pp. 4598-4607
Author(s):  
T Hoey ◽  
R Warrior ◽  
J Manak ◽  
M Levine

The homeo box gene even-skipped (eve) encodes a 376-amino-acid protein that binds with high affinity to sequences located near the 5' termini of the eve and en genes. The 5' en sites are A + T rich and contain copies of the 10-base-pair (bp) consensus sequence T-C-A-A-T-T-A-A-A-T. In contrast, the 5' eve sites are G + C rich and contain the 9-bp sequence T-C-A-G-C-A-C-C-G. Among the five different homeo box proteins that have been tested for binding, eve is unique in that it shows virtually equal preference for the A + T-rich 5' en binding sites and the G + C-rich 5' eve sites. Most of the other proteins bind with a relatively higher affinity to the en sites than to the eve sites. In an effort to identify the regions of the eve protein that are responsible for its efficient binding to both classes of recognition sequences, we analyzed the DNA-binding properties of various mutant eve proteins. These studies suggest that the homeo domain of the eve protein is responsible for both binding activities. However, mutations in distant regions of the protein influenced the binding behavior of the eve homeo domain and caused a reduction in binding to the G + C class of recognition sites. We propose that the protein context of the homeo domain can influence its DNA-binding properties.


2007 ◽  
Vol 189 (13) ◽  
pp. 4718-4728 ◽  
Author(s):  
Kim A. Susanna ◽  
Aleksandra M. Mironczuk ◽  
Wiep Klaas Smits ◽  
Leendert W. Hamoen ◽  
Oscar P. Kuipers

ABSTRACT The competence transcription factor ComK plays a central role in competence development in Bacillus subtilis by activating the transcription of the K regulon. ComK-activated genes are characterized by the presence of a specific sequence to which ComK binds, a K-box, in their upstream DNA region. Each K-box consists of two AT-boxes with the consensus sequence AAAA-(N)5-TTTT, which are separated by a flexible spacer resulting in either two, three, or four helical turns between the starting nucleotides of the repeating AT-box units. In this study, the effects of potential determinants of ComK regulation in K-boxes were investigated by testing ComK's transcription activation and DNA-binding affinity on altered K-boxes with mutations either in the spacer between the AT-boxes or in the consensus sequence of the AT-boxes. The most striking result demonstrates the importance of the second thymine base in the AT-boxes. Mutation of this T into a guanine resulted in a threefold reduction in transcription activation and DNA binding by ComK. Transcription activation, as well as DNA binding, was almost completely abolished when both AT-boxes contained a T2-to-G mutation. This result was corroborated by in silico analyses demonstrating that a combination of mutations at the T2 positions of both AT-boxes is not found among any ComK-activated K-boxes, indicating that at least one consensus T2 position is required to maintain a functional K-box. The results suggest an important structural role for T2 in ComK binding, probably by its specific position in the minor groove of the DNA.


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.


2021 ◽  
Vol 49 (7) ◽  
pp. 3856-3875
Author(s):  
Marina Kulik ◽  
Melissa Bothe ◽  
Gözde Kibar ◽  
Alisa Fuchs ◽  
Stefanie Schöne ◽  
...  

Abstract The glucocorticoid (GR) and androgen (AR) receptors execute unique functions in vivo, yet have nearly identical DNA binding specificities. To identify mechanisms that facilitate functional diversification among these transcription factor paralogs, we studied them in an equivalent cellular context. Analysis of chromatin and sequence suggest that divergent binding, and corresponding gene regulation, are driven by different abilities of AR and GR to interact with relatively inaccessible chromatin. Divergent genomic binding patterns can also be the result of subtle differences in DNA binding preference between AR and GR. Furthermore, the sequence composition of large regions (>10 kb) surrounding selectively occupied binding sites differs significantly, indicating a role for the sequence environment in guiding AR and GR to distinct binding sites. The comparison of binding sites that are shared shows that the specificity paradox can also be resolved by differences in the events that occur downstream of receptor binding. Specifically, shared binding sites display receptor-specific enhancer activity, cofactor recruitment and changes in histone modifications. Genomic deletion of shared binding sites demonstrates their contribution to directing receptor-specific gene regulation. Together, these data suggest that differences in genomic occupancy as well as divergence in the events that occur downstream of receptor binding direct functional diversification among transcription factor paralogs.


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