scholarly journals Drosophila Enhancer of Rudimentary Homolog, ERH, Is a Binding Partner of RPS3, RPL19, and DDIT4, Suggesting a Mechanism for the Nuclear Localization of ERH

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Stuart I. Tsubota ◽  
Anthony C. Phillips
Keyword(s):  
Amino Acid ◽  
Nuclear Localization ◽  
Cellular Proliferation ◽  
Notch Signaling Pathway ◽  
Nuclear Localization Signals ◽  
Amino Acid Region ◽  
Binding Partners ◽  
Enhancer Of Rudimentary ◽  
Necessary And Sufficient ◽  
Acid Region

The protein enhancer of rudimentary homolog, ERH, is a small, highly conserved protein that has been found in animals, plants, and protists. Genetic and biochemical interactions have implicated ERH in the regulation of pyrimidine biosynthesis, DNA replication, transcription, mRNA splicing, cellular proliferation, tumorigenesis, and the Notch signaling pathway. In vertebrates and insects, ERH is nuclearly localized; however, an examination of the ERH amino-acid sequence does not reveal any nuclear localization signals. In this paper we show that the first 24 amino acids contain sequences necessary and sufficient for nuclear localization. Through yeast two-hybrid screens, three new binding partners of ERH, RPS3, RPL19, and DDIT4, were identified. RPS3 was isolated from both human and Drosophila screens. These interactions suggest functions of ERH in cell growth, cancer, and DNA repair. The ERH sequences necessary for the interactions between ERH and RPS3 and RPL19 are mapped onto the same 24-amino-acid region in ERH which are necessary for nuclear localization, suggesting that ERH is localizing to the nucleus through binding to one of its DNA-binding partners, such as RPS3 or RPL19.

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.

scholarly journals Nuclear Import of the Retrotransposon Tf1 Is Governed by a Nuclear Localization Signal That Possesses a Unique Requirement for the FXFG Nuclear Pore Factor Nup124p

2000 ◽  
Vol 20 (20) ◽  
pp. 7798-7812 ◽  
Author(s):  
Van-Dinh Dang ◽  
Henry L. Levin
Keyword(s):  
Amino Acid ◽  
Nuclear Envelope ◽  
Nuclear Localization ◽  
Nuclear Import ◽  
Heterologous Protein ◽  
Simian Virus 40 ◽  
Nuclear Pore ◽  
Surprising Result ◽  
Gag Protein ◽  
Nuclear Localization Signals

ABSTRACT Retroviruses, such as human immunodeficiency virus, that infect nondividing cells generate integration precursors that must cross the nuclear envelope to reach the host genome. As a model for retroviruses, we investigated the nuclear entry of Tf1, a long-terminal-repeat-containing retrotransposon of the fission yeastSchizosaccharomyces pombe. Because the nuclear envelope of yeasts remains intact throughout the cell cycle, components of Tf1 must be transported through the envelope before integration can occur. The nuclear localization of the Gag protein of Tf1 is different from that of other proteins tested in that it has a specific requirement for the FXFG nuclear pore factor, Nup124p. Using extensive mutagenesis, we found that Gag contained three nuclear localization signals (NLSs) which, when included individually in a heterologous protein, were sufficient to direct nuclear import. In the context of the intact transposon, mutations in the NLS that mapped to the first 10 amino acid residues of Gag significantly impaired Tf1 retrotransposition and abolished nuclear localization of Gag. Interestingly, this NLS activity in the heterologous protein was specifically dependent upon the presence of Nup124p. Deletion analysis of heterologous proteins revealed the surprising result that the residues in Gag with the NLS activity were independent from the residues that conveyed the requirement for Nup124p. In fact, a fragment of Gag that lacked NLS activity, residues 10 to 30, when fused to a heterologous protein, was sufficient to cause the classical NLS of simian virus 40 to require Nup124p for nuclear import. Within the context of the current understanding of nuclear import, these results represent the novel case of a short amino acid sequence that specifies the need for a particular nuclear pore complex protein.

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
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