scholarly journals Characterization of LrpC DNA-Binding Properties and Regulation of Bacillus subtilis lrpC Gene Expression

2000 ◽  
Vol 182 (16) ◽  
pp. 4414-4424 ◽  
Author(s):  
Christophe Beloin ◽  
Rachel Exley ◽  
Anne-Laure Mahé ◽  
Mohamed Zouine ◽  
Stephanie Cubasch ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Biological Significance ◽  
Stationary Growth Phase ◽  
Upstream Region ◽  
Binding Properties ◽  
Sequencing Project ◽  
Dna Binding Properties ◽  
Transcriptional Fusions

ABSTRACT The lrpC gene was identified during the Bacillus subtilis genome sequencing project. Previous experiments suggested that LrpC has a role in sporulation and in the regulation of amino acid metabolism and that it shares features withEscherichia coli Lrp, a transcription regulator (C. Beloin, S. Ayora, R. Exley, L. Hirschbein, N. Ogasawara, Y. Kasahara, J. C. Alonso, and F. Le Hégarat, Mol. Gen. Genet. 256:63–71, 1997). To characterize the interactions of LrpC with DNA, the protein was overproduced and purified. We show that LrpC binds to multiple sites in the upstream region of its own gene with a stronger affinity for a region encompassing P1, one of the putative promoters identified (P1 and P2). By analyzing lrpC-lacZ transcriptional fusions, we demonstrated that P1 is the major in vivo promoter and that, unlike many members of the lrp/asnC family,lrpC is not negatively autoregulated but rather slightly positively autoregulated. Production of LrpC in vivo is low in both rich and minimal media (50 to 300 LrpC molecules per cell). In rich medium, the cellular LrpC content is six- to sevenfold lower during the exponentional phase than during the stationary growth phase. Possible determinants and the biological significance of the regulation oflrpC expression are discussed.

scholarly journals The −10 Region Is a Key Promoter Specificity Determinant for the Bacillus subtilis Extracytoplasmic-Function ς Factors ςX and ςW

2001 ◽  
Vol 183 (6) ◽  
pp. 1921-1927 ◽  
Author(s):  
Jian Qiu ◽  
John D. Helmann
Keyword(s):  
Bacillus Subtilis ◽  
Amino Acid ◽  
Rna Polymerase ◽  
Context Effects ◽  
Promoter Strength ◽  
Binding Properties ◽  
Promoter Specificity ◽  
Dna Binding Properties

ABSTRACT Transcriptional selectivity derives, in large part, from the sequence-specific DNA-binding properties of the ς subunit of RNA polymerase. There are 17 ς factors in Bacillus subtilis which, in general, recognize distinct sets of promoters. However, some ς factors have overlapping promoter selectivity. We hypothesize that the overlap between the regulons activated by the ςX and ςW factors can be explained by overlapping specificity for the −10 region: ςX recognizes −10 elements with the sequence CGAC and ςW recognizes CGTA, while both can potentially recognize CGTC. To test this model, we mutated the ςX-specific autoregulatory site (PX), containing the −10 element CGAC, to either CGTC or GCTA. Conversely, the ςW autoregulatory site (PW) was altered from CGTA to CGTC or CGAC. Transcriptional analyses, both in vitro and in vivo, indicate that changes to the −10 element are sufficient to switch a promoter from the ςX to the ςW regulon or, conversely, from the ςW to the ςX regulon, but context effects clearly play an important role in determining promoter strength. It seems likely that these subtle differences in promoter selectivity derive from amino acid differences in conserved region 2 of ς, which contacts the −10 element. However, we were unable to alter promoter selectivity by replacements of two candidate recognition residues in ςW.

scholarly journals Molecular Characterization of HOXA2 and HOXA3 Binding Properties

2021 ◽  
Vol 9 (4) ◽  
pp. 55
Author(s):  
Joshua Mallen ◽  
Manisha Kalsan ◽  
Peyman Zarrineh ◽  
Laure Bridoux ◽  
Shandar Ahmad ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Molecular Characterization ◽  
Sequence Motif ◽  
Body Parts ◽  
Binding Affinities ◽  
Binding Properties ◽  
Functional Consequences

The highly conserved HOX homeodomain (HD) transcription factors (TFs) establish the identity of different body parts along the antero–posterior axis of bilaterian animals. Segment diversification and the morphogenesis of different structures is achieved by generating precise patterns of HOX expression along the antero–posterior axis and by the ability of different HOX TFs to instruct unique and specific transcriptional programs. However, HOX binding properties in vitro, characterised by the recognition of similar AT-rich binding sequences, do not account for the ability of different HOX to instruct segment-specific transcriptional programs. To address this problem, we previously compared HOXA2 and HOXA3 binding in vivo. Here, we explore if sequence motif enrichments observed in vivo are explained by binding affinities in vitro. Unexpectedly, we found that the highest enriched motif in HOXA2 peaks was not recognised by HOXA2 in vitro, highlighting the importance of investigating HOX binding in its physiological context. We also report the ability of HOXA2 and HOXA3 to heterodimerise, which may have functional consequences for the HOX patterning function in vivo.

In vivo functional characterization of an ecdysone response enhancer in the proximal upstream region of the Fbp1 gene of D. melanogaster

1993 ◽  
Vol 44 (2-3) ◽  
pp. 123-138 ◽  
Author(s):  
Monique Laval ◽  
Francine Pourrain ◽  
Jean Deutsch ◽  
Jean-Antoine Lepesant
Keyword(s):  
Functional Characterization ◽  
Upstream Region ◽  
Fbp1 Gene

Synthesis, crystal structure and characterization of three novel copper complexes of Levofloxacin. Study of their DNA binding properties and biological activities

2014 ◽  
Vol 423 ◽  
pp. 207-218 ◽  
Author(s):  
Anastasia Galani ◽  
Eleni K. Efthimiadou ◽  
George Mitrikas ◽  
Yiannis Sanakis ◽  
Vassilis Psycharis ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Dna Binding ◽  
Copper Complexes ◽  
Biological Activities ◽  
Binding Properties ◽  
Dna Binding Properties
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