scholarly journals A divergent CheW confers plasticity to nucleoid-associated chemosensory arrays

2017 ◽  
Author(s):  
Annick Guiseppi ◽  
Juan Jesus Vicente ◽  
Julien Herrou ◽  
Deborah Byrne ◽  
Aurelie Barneoud ◽  
...  
Keyword(s):  
Amino Acid ◽  
Histidine Kinase ◽  
Environmental Changes ◽  
Myxococcus Xanthus ◽  
Accessory Protein ◽  
Cellular Functions ◽  
The Core ◽  
Amino Acid Region ◽  
Chemosensory Systems ◽  
Acid Region

ABSTRACTChemosensory systems are highly organized signaling pathways that allow bacteria to adapt to environmental changes. The Frz chemosensory system from M. xanthus possesses two CheW-like proteins, FrzA (the core CheW) and FrzB. We found that FrzB does not interact with FrzE (the cognate CheA) as it lacks the amino acid region responsible for this interaction. FrzB, instead, acts upstream of FrzCD in the regulation of M. xanthus chemotaxis behaviors and activates the Frz pathway by allowing the formation and distribution of multiple chemosensory clusters on the nucleoid. These results, together, show that the lack of the CheA-interacting region in FrzB confers new functions to this small protein.AUTHOR SUMMARYChemosensory systems are signaling complexes that are widespread in bacteria and allow the modulation of different cellular functions, such as taxis and development, in response to the environment. We show that the Myxococcus xanthus FrzB is a divergent CheW lacking the region involved in the interaction with the histidine kinase FrzE. Instead, it acts upstream of FrzCD to allow the formation of multiple distributed Frz chemosensory arrays at the nucleoid. The loss of the CheA-interacting region in FrzB might have been selected to confer plasticity to nucleoid-associated chemosensory systems. By unraveling a new accessory protein and its function, this work opens new insights into the knowledge of the regulatory potentials of bacterial chemosensory systems.

scholarly journals A Carboxy-Terminal 16-Amino-Acid Region of ς38 ofEscherichia coli Is Important for Transcription under High-Salt Conditions and Sigma Activities In Vivo

2000 ◽  
Vol 182 (16) ◽  
pp. 4628-4631 ◽  
Author(s):  
Mio Ohnuma ◽  
Nobuyuki Fujita ◽  
Akira Ishihama ◽  
Kan Tanaka ◽  
Hideo Takahashi
Keyword(s):  
Amino Acid ◽  
Bacterial Species ◽  
High Potassium ◽  
Transcription Analysis ◽  
Amino Acid Region ◽  
Sigma Subunit ◽  
Carboxy Terminal ◽  
Acid Region

ABSTRACT ς38 (or ςS, the rpoS gene product) is a sigma subunit of RNA polymerase in Escherichia coli and directs transcription from a number of stationary-phase promoters as well as osmotically inducible promoters. In this study, we analyzed the function of the carboxy-terminal 16-amino-acid region of ς38 (residues 315 to 330), which is well conserved among the rpoS gene products of enteric bacterial species. Truncation of this region was shown to result in the loss of sigma activity in vivo using promoter-lacZ fusion constructs, but the mutant ς38 retained the binding activity in vivo to the core enzyme. The in vitro transcription analysis revealed that the transcription activity of ς38 holoenzyme under high potassium glutamate concentrations was significantly decreased by the truncation of the carboxy-terminal tail element.

scholarly journals The DNA-binding specificity of the hepatocyte nuclear factor 3/forkhead domain is influenced by amino-acid residues adjacent to the recognition helix.

1994 ◽  
Vol 14 (4) ◽  
pp. 2755-2766 ◽  
Author(s):  
D G Overdier ◽  
A Porcella ◽  
R H Costa
Keyword(s):  
Amino Acid ◽  
Dna Binding ◽  
Hepatocyte Nuclear Factor ◽  
Binding Properties ◽  
Winged Helix ◽  
Amino Acid Region ◽  
Dna Binding Specificity ◽  
Recognition Helix ◽  
Dna Binding Properties ◽  
Acid Region

Three distinct hepatocyte nuclear factor 3 (HNF-3) proteins (HNF-3 alpha, -3 beta, and -3 gamma) are known to regulate the transcription of liver-specific genes. The HNF-3 proteins bind to DNA as a monomer through a modified helix-turn-helix, known as the winged helix motif, which is also utilized by a number of developmental regulators, including the Drosophila homeotic forkhead (fkh) protein. We have previously described the isolation, from rodent tissue, of an extensive family of tissue-specific HNF-3/fkh homolog (HFH) genes sharing homology in their winged helix motifs. In this report, we have determined the preferred DNA-binding consensus sequence for the HNF-3 beta protein as well as for two divergent family members, HFH-1 and HFH-2. We show that these HNF-3/fkh proteins bind to distinct DNA sites and that the specificity of protein recognition is dependent on subtle nucleotide alterations in the site. The HNF-3, HFH-1, and HFH-2 consensus binding sequences were also used to search DNA regulatory regions to identify potential target genes. Furthermore, an analysis of the DNA-binding properties of a series of HFH-1/HNF-3 beta protein chimeras has allowed us to identify a 20-amino-acid region, located adjacent to the DNA recognition helix, which contributes to DNA-binding specificity. These sequences are not involved in base-specific contacts and include residues which diverge within the HNF-3/fkh family. Replacement of this 20-amino-acid region in HNF-3 beta with corresponding residues from HFH-1 enabled the HNF-3 beta recognition helix to bind only HFH-1-specific DNA-binding sites. We propose a model in which this 20-amino-acid flanking region influences the DNA-binding properties of the recognition helix.

scholarly journals Rho1p-Bni1p-Spa2p Interactions: Implication in Localization of Bni1p at the Bud Site and Regulation of the Actin Cytoskeleton inSaccharomyces cerevisiae

1998 ◽  
Vol 9 (5) ◽  
pp. 1221-1233 ◽  
Author(s):  
Takeshi Fujiwara ◽  
Kazuma Tanaka ◽  
Akihisa Mino ◽  
Mitsuhiro Kikyo ◽  
Kazuo Takahashi ◽  
...  
Keyword(s):  
Amino Acid ◽  
Actin Cytoskeleton ◽  
Binding Protein ◽  
Microscopic Analysis ◽  
Mitogen Activated Protein Kinase ◽  
Gene Encoding ◽  
Amino Acid Region ◽  
Genes Encoding ◽  
Mitogen Activated Protein ◽  
Acid Region

Rho1p is a yeast homolog of mammalian RhoA small GTP-binding protein. Rho1p is localized at the growth sites and required for bud formation. We have recently shown that Bni1p is a potential target of Rho1p and that Bni1p regulates reorganization of the actin cytoskeleton through interactions with profilin, an actin monomer-binding protein. Using the yeast two-hybrid screening system, we cloned a gene encoding a protein that interacted with Bni1p. This protein, Spa2p, was known to be localized at the bud tip and to be implicated in the establishment of cell polarity. The C-terminal 254 amino acid region of Spa2p, Spa2p(1213–1466), directly bound to a 162-amino acid region of Bni1p, Bni1p(826–987). Genetic analyses revealed that both thebni1 and spa2 mutations showed synthetic lethal interactions with mutations in the genes encoding components of the Pkc1p-mitogen-activated protein kinase pathway, in which Pkc1p is another target of Rho1p. Immunofluorescence microscopic analysis showed that Bni1p was localized at the bud tip in wild-type cells. However, in the spa2 mutant, Bni1p was not localized at the bud tip and instead localized diffusely in the cytoplasm. A mutant Bni1p, which lacked the Rho1p-binding region, also failed to be localized at the bud tip. These results indicate that both Rho1p and Spa2p are involved in the localization of Bni1p at the growth sites where Rho1p regulates reorganization of the actin cytoskeleton through Bni1p.

The F12-Vif derivative Chim3 inhibits HIV-1 replication in CD4+ T lymphocytes and CD34+-derived macrophages by blocking HIV-1 DNA integration

Blood ◽  
2009 ◽  
Vol 113 (15) ◽  
pp. 3443-3452 ◽  
Author(s):  
Simona Porcellini ◽  
Luca Alberici ◽  
Francesco Gubinelli ◽  
Rossella Lupo ◽  
Clelia Olgiati ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Amino Acid ◽  
T Lymphocytes ◽  
Genetic Manipulation ◽  
Natural Resistance ◽  
Dna Integration ◽  
Amino Acid Region ◽  
Antiviral Function ◽  
Hiv 1 ◽  
Acid Region

Abstract The viral infectivity factor (Vif) is essential for HIV-1 infectivity and hence is an ideal target for promising anti–HIV-1/AIDS gene therapy. We previously demonstrated that F12-Vif mutant inhibits HIV-1 replication in CD4+ T lymphocytes. Despite macrophage relevance to HIV-1 pathogenesis, most gene therapy studies do not investigate macrophages because of their natural resistance to genetic manipulation. Here, we confirm the F12-Vif antiviral activity also in macrophages differentiated in vitro from transduced CD34+ human stem cells (HSCs). Moreover, we identified the 126- to 170-amino-acid region in the C-terminal half of F12-Vif as responsible for its antiviral function. Indeed, Chim3 protein, containing this 45-amino-acid region embedded in a WT-Vif backbone, is as lethal as F12-Vif against HIV-1. Of major relevance, we demonstrated a dual mechanism of action for Chim3. First, Chim3 functions as a transdominant factor that preserves the antiviral function of the natural restriction factor APOBEC3G (hA3G). Second, Chim3 blocks the early HIV-1 retrotranscript accumulation and thereby HIV-1 DNA integration regardless of the presence of WT-Vif and hA3G. In conclusion, by impairing the early steps of HIV-1 life cycle, Chim3 conceivably endows engineered cells with survival advantage, which is required for the efficient immune reconstitution of patients living with HIV/AIDS.

Identification of an amino acid region supporting specific methionyl-tRNA synthetase: tRNA recognition

1989 ◽  
Vol 208 (3) ◽  
pp. 429-443 ◽  
Author(s):  
Patrice Mellot ◽  
Yves Mechulam ◽  
Daniel Le Corre ◽  
Sylvain Blanquet ◽  
Guy Fayat
Keyword(s):  
Amino Acid ◽  
Trna Synthetase ◽  
Trna Recognition ◽  
Amino Acid Region ◽  
Methionyl Trna Synthetase ◽  
Acid Region

scholarly journals Contribution of Amino Acid Region 334−335 from Factor Va Heavy Chain to the Catalytic Efficiency of Prothrombinase†

Biochemistry ◽  
2008 ◽  
Vol 47 (26) ◽  
pp. 6840-6850 ◽  
Author(s):  
Melissa A. Barhoover ◽  
Tivadar Orban ◽  
Daniel O. Beck ◽  
Michael A. Bukys ◽  
Michael Kalafatis
Keyword(s):  
Amino Acid ◽  
Heavy Chain ◽  
Catalytic Efficiency ◽  
Amino Acid Region ◽  
Factor Va ◽  
Acid Region

scholarly journals The human myeloid cell nuclear differentiation antigen gene is one of at least two related interferon-inducible genes located on chromosome 1q that are expressed specifically in hematopoietic cells

Blood ◽  
1994 ◽  
Vol 83 (8) ◽  
pp. 2153-2162 ◽  
Author(s):  
RC Briggs ◽  
JA Briggs ◽  
J Ozer ◽  
L Sealy ◽  
LL Dworkin ◽  
...  
Keyword(s):  
Amino Acid ◽  
Human Chromosome ◽  
Gene Family ◽  
Myeloid Cell ◽  
Human Monocytes ◽  
Differentiation Antigen ◽  
Chromosome 1Q ◽  
Amino Acid Region ◽  
Nuclear Differentiation ◽  
Acid Region

We have previously shown that the human myeloid cell nuclear differentiation antigen (MNDA) is expressed at both the antigen and mRNA levels specifically in human monocytes and granulocytes and earlier stage cells in the myeloid lineage. A 200 amino acid region of the MNDA is strikingly similar to a region in the proteins encoded by a family of interferon-inducible mouse genes, designated Ifi-201, Ifi- 202, Ifi-203, etc, that are not regulated in a cell- or tissue-specific fashion. However, a new member of the Ifi-200 gene family, D3, is induced in mouse mononuclear phagocytes but not in fibroblasts by interferon. The same 200 amino acid region, duplicated in the mouse Ifi- 200 gene family, is also repeated in the recently characterized human IFI 16 gene that is constitutively expressed specifically in lymphoid cells and is induced in myeloid cells by interferon gamma. The 1.8-kb MNDA mRNA, which contains an interferon-stimulated response element in the 5′ untranslated region, was significantly upregulated in human monocytes exposed to interferon alpha. Characterization of the MNDA gene showed that it is a single-copy gene and localized to human chromosome 1q 21–22 within the large linkage group conserved between mouse and human that contains the Ifi-200 gene family. The IFI 16 gene is also located on human chromosome 1q. Our observations are consistent with the proposal that the MNDA is a member of a cluster of related human interferon-regulated genes, similar to the mouse Ifi-200 gene family. In addition, one mouse gene in the Ifi-200 gene family and the human MNDA and IFI 16 genes show expression and/or regulation restricted to cells of the hematopoietic system, suggesting that these genes participate in blood cell-specific responses to interferons.

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