scholarly journals Monoclonal antibody Y13-259 recognizes an epitope of the p21 ras molecule not directly involved in the GTP-binding activity of the protein.

1986 ◽  
Vol 6 (4) ◽  
pp. 1002-1009 ◽  
Author(s):  
J C Lacal ◽  
S A Aaronson
Keyword(s):  
Monoclonal Antibody ◽  
Amino Acid ◽  
Dna Synthesis ◽  
Binding Activity ◽  
Structural Domain ◽  
Serum Stimulation ◽  
Amino Acid Region ◽  
Gtp Binding ◽  
P21 Ras

The p21 products of ras proto-oncogenes are GTP-binding proteins with associated GTPase activity. Recent studies have indicated that ras p21 may be required for the initiation of normal cell DNA synthesis, since microinjection of a monoclonal antibody, Y13-259, blocks serum stimulation of DNA synthesis in quiescent cell cultures (L. S. Mulcahy, M.R. Smith, and D. W. Stacey, Nature [London] 313:241-243, 1985). We localized the structural domain within the p21 molecule recognized by the Y13-259 monoclonal antibody. By analysis of a series of bacterially expressed p21 deletion mutants, the monoclonal antibody was found to interact with a region between positions 70 and 89 in the p21 amino acid sequence. By comparison of the coding sequences of different p21 proteins recognized by this monoclonal antibody, a highly conserved amino acid region between positions 70 and 81 was found to be the most likely site for the epitope detected by the Y13-259 antibody. This monoclonal antibody was further shown not to interfere directly with in vitro biochemical functions of the molecule, including GTP binding, GTPase, and autokinase activities.

Monoclonal antibody Y13-259 recognizes an epitope of the p21 ras molecule not directly involved in the GTP-binding activity of the protein

1986 ◽  
Vol 6 (4) ◽  
pp. 1002-1009
Author(s):  
J C Lacal ◽  
S A Aaronson
Keyword(s):  
Monoclonal Antibody ◽  
Amino Acid ◽  
Dna Synthesis ◽  
Binding Activity ◽  
Structural Domain ◽  
Serum Stimulation ◽  
Amino Acid Region ◽  
Gtp Binding ◽  
P21 Ras

The p21 products of ras proto-oncogenes are GTP-binding proteins with associated GTPase activity. Recent studies have indicated that ras p21 may be required for the initiation of normal cell DNA synthesis, since microinjection of a monoclonal antibody, Y13-259, blocks serum stimulation of DNA synthesis in quiescent cell cultures (L. S. Mulcahy, M.R. Smith, and D. W. Stacey, Nature [London] 313:241-243, 1985). We localized the structural domain within the p21 molecule recognized by the Y13-259 monoclonal antibody. By analysis of a series of bacterially expressed p21 deletion mutants, the monoclonal antibody was found to interact with a region between positions 70 and 89 in the p21 amino acid sequence. By comparison of the coding sequences of different p21 proteins recognized by this monoclonal antibody, a highly conserved amino acid region between positions 70 and 81 was found to be the most likely site for the epitope detected by the Y13-259 antibody. This monoclonal antibody was further shown not to interfere directly with in vitro biochemical functions of the molecule, including GTP binding, GTPase, and autokinase activities.

scholarly journals MBDin, a Novel MBD2-Interacting Protein, Relieves MBD2 Repression Potential and Reactivates Transcription from Methylated Promoters

2003 ◽  
Vol 23 (5) ◽  
pp. 1656-1665 ◽  
Author(s):  
Francesca Lembo ◽  
Raffaela Pero ◽  
Tiziana Angrisano ◽  
Carmen Vitiello ◽  
Rodolfo Iuliano ◽  
...  
Keyword(s):  
Amino Acid ◽  
Binding Site ◽  
Nuclear Export ◽  
Mammalian Cells ◽  
Nuclear Export Signal ◽  
Interacting Protein ◽  
Amino Acid Region ◽  
Gtp Binding ◽  
Acid Region

ABSTRACT We have identified a human gene encoding a novel MBD2-interacting protein (MBDin) that contains an N-terminal GTP-binding site, a putative nuclear export signal (NES), and a C-terminal acidic region. MBDin cDNA was isolated through a two-hybrid interaction screening using the methyl-CpG-binding protein MBD2 as bait. The presence of the C-terminal 46-amino-acid region of MBD2 and both the presence of the acidic C-terminal 128-amino-acid region and the integrity of the GTP-binding site of MBDin were required for the interaction. Interaction between MBD2 and MBDin in mammalian cells was confirmed by immunoprecipitation experiments. Fluorescence imaging experiments demonstrated that MBDin mainly localizes in the cytoplasm but accumulates in the nucleus upon disruption of the NES or treatment with leptomycin B, an inhibitor of NES-mediated transport. We also found that MBDin partially colocalizes with MBD2 at foci of heavily methylated satellite DNA. An MBD2 deletion mutant lacking the C-terminal region maintained its subnuclear localization but failed to recruit MBDin at hypermethylated foci. Functional analyses demonstrated that MBDin relieves MBD2-mediated transcriptional repression both when Gal4 chimeric constructs and when in vitro-methylated promoter-reporter plasmids were used in transcriptional assays. Southern blotting and bisulfite analysis showed that transcriptional reactivation occurred without changes of the promoter methylation pattern. Our findings suggest the existence of factors that could be targeted on methylated DNA by methyl-CpG-binding proteins reactivating transcription even prior to demethylation.

scholarly journals Truncated mammalian Notch1 activates CBF1/RBPJk-repressed genes by a mechanism resembling that of Epstein-Barr virus EBNA2.

1996 ◽  
Vol 16 (3) ◽  
pp. 952-959 ◽  
Author(s):  
J J Hsieh ◽  
T Henkel ◽  
P Salmon ◽  
E Robey ◽  
M G Peterson ◽  
...  
Keyword(s):  
Amino Acid ◽  
Cell Fate ◽  
Transcriptional Repression ◽  
Epstein Barr Virus ◽  
Cell Fate Decisions ◽  
Barr Virus ◽  
Amino Acid Region ◽  
Nuclear Events ◽  
Epstein Barr

The Notch/Lin-12/Glp-1 receptor family participates in cell-cell signaling events that influence cell fate decisions. Although several Notch homologs and receptor ligands have been identified, the nuclear events involved in this pathway remain incompletely understood. A truncated form of Notch, consisting only of the intracellular domain (NotchIC), localizes to the nucleus and functions as an activated receptor. Using both an in vitro binding assay and a cotransfection assay based on the two-hybrid principle, we show that mammalian NotchIC interacts with the transcriptional repressor CBF1, which is the human homolog of Drosophila Suppressor of Hairless. Cotransfection assays using segments of mouse NotchIC and CBF1 demonstrated that the N-terminal 114-amino-acid region of mouse NotchIC contains the CBF1 interactive domain and that the cdc10/ankyrin repeats are not essential for this interaction. This result was confirmed in immunoprecipation assays in which the N-terminal 114-amino-acid segment of NotchIC, but not the ankyrin repeat region, coprecipitated with CBF1. Mouse NotchIC itself is targeted to the transcriptional repression domain (aa179 to 361) of CBF1. Furthermore, transfection assays in which mouse NotchIC was targeted through Gal4-CBF1 or through endogenous cellular CBF1 indicated that NotchIC transactivates gene expression via CBF1 tethering to DNA. Transactivation by NotchIC occurs partially through abolition of CBF1-mediated repession. This same mechanism is used by Epstein-Barr virus EBNA2. Thus, mimicry of Notch signal transduction is involved in Epstein-Barr virus-driven immortalization.

Definition of Essential Amino Acid Residues in the Recognition of a Peptide by a Mouse Monoclonal Antibody

1997 ◽  
Vol 52 (3-4) ◽  
pp. 274-278
Author(s):  
Laura Rosanó ◽  
Francesca Di Modugno ◽  
Giulia Romagnoli ◽  
Alberto Chersi
Keyword(s):  
Monoclonal Antibody ◽  
Amino Acid ◽  
Critical Role ◽  
Binding Activity ◽  
Mouse Monoclonal Antibody ◽  
Amino Acid Residues ◽  
Binding Data ◽  
Amino Acid Stretch ◽  
Definition Of ◽  
Key Residues

AbstractA mouse monoclonal antibody reacting in ELISA with a synthetic peptide representing a linear amino acid stretch of the protein antigen was tested on all overlap­ ping 5-mer to 9-mer fragments of the peptide, as prepared by multi-pin synthesis. Analysis of the binding data suggests that several residues in the peptide might be relatively unrelevant for recognition, while few others seem to play a critical role as key residues. On the basis of such observations, we attempted to reconstruct an alternative essential epitope by introducing multiple amino acid substitutions in the 9-mer peptide exhibiting the best binding activity, and then tested its ability to be recognized by the monoclonal antibody.

scholarly journals Identification of Mimotope Peptides Which Bind to the Mycotoxin Deoxynivalenol-Specific Monoclonal Antibody

1999 ◽  
Vol 65 (8) ◽  
pp. 3279-3286 ◽  
Author(s):  
Qiaoping Yuan ◽  
James J. Pestka ◽  
Brandon M. Hespenheide ◽  
Leslie A. Kuhn ◽  
John E. Linz ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Alkaline Phosphatase ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Synthetic Peptide ◽  
Amino Acid Sequences ◽  
In Vitro Translation ◽  
Enzyme Linked Immunosorbent Assay ◽  
Translation System

ABSTRACT Monoclonal antibody 6F5 (mAb 6F5), which recognizes the mycotoxin deoxynivalenol (DON) (vomitoxin), was used to select for peptides that mimic the mycotoxin by employing a library of filamentous phages that have random 7-mer peptides on their surfaces. Two phage clones selected from the random peptide phage-displayed library coded for the amino acid sequences SWGPFPF and SWGPLPF. These clones were designated DONPEP.2 and DONPEP.12, respectively. The results of a competitive enzyme-linked immunosorbent assay (ELISA) suggested that the two phage displayed peptides bound to mAb 6F5 specifically at the DON binding site. The amino acid sequence of DONPEP.2 plus a structurally flexible linker at the C terminus (SWGPFPFGGGSC) was synthesized and tested to determine its ability to bind to mAb 6F5. This synthetic peptide (designated peptide C430) and DON competed with each other for mAb 6F5 binding. When translationally fused with bacterial alkaline phosphatase, DONPEP.2 bound specifically to mAb 6F5, while the fusion protein retained alkaline phosphatase activity. The potential of using DONPEP.2 as an immunochemical reagent in a DON immunoassay was evaluated with a DON-spiked wheat extract. When peptide C430 was conjugated to bovine serum albumin, it elicited antibody specific to peptide C430 but not to DON in both mice and rabbits. In an in vitro translation system containing rabbit reticulocyte lysate, synthetic peptide C430 did not inhibit protein synthesis but did show antagonism toward DON-induced protein synthesis inhibition. These data suggest that the peptides selected in this study bind to mAb 6F5 and that peptide C430 binds to ribosomes at the same sites as DON.

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 Transglutaminase 5 is regulated by guanine–adenine nucleotides1

2004 ◽  
Vol 381 (1) ◽  
pp. 313-319 ◽  
Author(s):  
Eleonora CANDI ◽  
Andrea PARADISI ◽  
Alessandro TERRINONI ◽  
Valentina PIETRONI ◽  
Sergio ODDI ◽  
...  
Keyword(s):  
Amino Acid ◽  
Three Dimensional ◽  
Binding Pocket ◽  
Cross Linking ◽  
Bifunctional Enzyme ◽  
Amino Acid Sequence Alignment ◽  
Gtp Binding ◽  
Epidermal Tissue ◽  
Isopeptide Bonds

Transglutaminases (TGases) are Ca2+-dependent enzymes capable of catalysing transamidation of glutamine residues to form intermolecular isopeptide bonds. Nine distinct TGases have been described in mammals, and two of them (types 2 and 3) are regulated by GTP/ATP. TGase2 hydrolyses GTP and is therefore a bifunctional enzyme. In the present study, we report that TGase5 is also regulated by nucleotides. We have identified the putative TGase5 GTP-binding pocket by comparative amino acid sequence alignment and homology-derived three-dimensional modelling. GTP and ATP inhibit TGase5 cross-linking activity in vitro, and Ca2+ is capable of completely reversing this inhibition. In addition, TGase5 mRNA is not restricted to epidermal tissue, but is also present in different adult and foetal tissues, suggesting a role for TGase5 outside the epidermis. These results reveal the reciprocal actions of Ca2+ and nucleotides with respect to TGase5 activity. Taken together, these results indicate that TGases are a complex family of enzymes regulated by calcium, with at least three of them, namely TGase2, TGase3 and TGase5, also being regulated by ATP and GTP.

scholarly journals Jun is phosphorylated by several protein kinases at the same sites that are modified in serum-stimulated fibroblasts.

1992 ◽  
Vol 12 (10) ◽  
pp. 4694-4705 ◽  
Author(s):  
S J Baker ◽  
T K Kerppola ◽  
D Luk ◽  
M T Vandenberg ◽  
D R Marshak ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Dna Binding ◽  
Glycogen Synthase ◽  
In Vitro Transcription ◽  
Binding Activity ◽  
Dna Binding Activity ◽  
Serum Stimulation ◽  
Dependent Protein

c-jun is a member of the family of immediate-early genes whose expression is induced by factors such as serum stimulation, phorbol ester, and differentiation signals. Here we show that increased Jun synthesis after serum stimulation is accompanied by a concomitant increase in phosphorylation. Several serine-threonine kinases were evaluated for their ability to phosphorylate Jun in vitro. p34cdc2, protein kinase C, casein kinase II, and pp44mapk phosphorylated Jun efficiently, whereas cyclic AMP-dependent protein kinase and glycogen synthase kinase III did not. The sites phosphorylated by p34cdc2 were similar to those phosphorylated in vivo after serum induction. The major sites of phosphorylation were mapped to serines 63, 73, and 246. Phosphorylation of full-length Jun with several kinases did not affect the DNA-binding activity of Jun homodimers or Fos-Jun heterodimers. Comparison of the DNA binding and in vitro transcription properties of wild-type and mutated proteins containing either alanine or aspartic acid residues in place of Ser-63, -73, and -246 revealed only minor differences among homodimeric complexes and no differences among Fos-Jun heterodimers. Thus, phosphorylation of Jun did not produce a significant change in dimerization, DNA-binding, or in vitro transcription activity. The regulatory role of phosphorylation in the modulation of Jun function is likely to be considerably more complex than previously suggested.

scholarly journals cpc-1, the general regulatory gene for genes of amino acid biosynthesis in Neurospora crassa, is differentially expressed during the asexual life cycle

1991 ◽  
Vol 11 (2) ◽  
pp. 928-934 ◽  
Author(s):  
D J Ebbole ◽  
J L Paluh ◽  
M Plamann ◽  
M S Sachs ◽  
C Yanofsky
Keyword(s):  
Amino Acid ◽  
Dna Binding ◽  
Neurospora Crassa ◽  
Regulatory Gene ◽  
Regulatory Protein ◽  
Binding Activity ◽  
Recognition Sequence ◽  
Dna Binding Activity ◽  
Cell Extracts

CPCI, the principal regulatory protein required for cross-pathway control of amino acid biosynthetic genes in Neurospora crassa, contains a domain similar to the DNA-binding domain of GCN4, the corresponding general regulator in Saccharomyces cerevisiae. We examined binding by CPC1 synthesized in vitro and by CPC1 present in N. crassa whole-cell extracts. CPCI from both sources was shown to bind to the DNA sequence 5'-ATGACTCAT-3', which is also the preferred recognition sequence of GCN4, CPC1 was confirmed as the source of DNA-binding activity in extracts by immunoblotting. Slightly mobility differences between DNA complexes containing CPCI synthesized in vitro and CPC1 in mycelial extracts were observed. Analyses of N. crassa extracts from different stages of asexual development revealed that CPC1 was abundant immediately following spore germination and through early mycelial growth but was scarce subsequently. CPC1 levels could be increased at any time by imposing amino acid starvation. Copies of the CPC1 response element are located upstream of several genes regulated by cross-pathway control, including cpc-1 itself.

scholarly journals Functional and conserved domains of the Drosophila transcription factor encoded by the segmentation gene knirps

1994 ◽  
Vol 14 (12) ◽  
pp. 7899-7908
Author(s):  
N Gerwin ◽  
A La Rosée ◽  
F Sauer ◽  
H P Halbritter ◽  
M Neumann ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Amino Acid ◽  
Dna Binding ◽  
Broad Band ◽  
Binding Domain ◽  
Orphan Receptor ◽  
Dna Binding Domain ◽  
Coding Region ◽  
Amino Acid Region

The Drosophila gap gene knirps (kni) is required for abdominal segmentation. It encodes a steroid/thyroid orphan receptor-type transcription factor which is distributed in a broad band of nuclei in the posterior region of the blastoderm. To identify essential domains of the kni protein (KNI), we cloned and sequenced the DNA encompassing the coding region of nine kni mutant alleles of different strength and kni-homologous genes of related insect species. We also examined in vitro-modified versions of KNI in various assay systems both in vitro and in tissue culture. The results show that KNI contains several functional domains which are arranged in a modular fashion. The N-terminal 185-amino-acid region which includes the DNA-binding domain and a functional nuclear location signal fails to provide kni activity to the embryo. However, a truncated KNI protein that contains additional 47 amino acids exerts rather strong kni activity which is functionally defined by a weak kni mutant phenotype of the embryo. The additional 47-amino-acid stretch includes a transcriptional repressor domain which acts in the context of a heterologous DNA-binding domain of the yeast transcriptional activator GAL4. The different domains of KNI as defined by functional studies are conserved during insect evolution.

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