Search results for "binding sites"
showing 10 items of 636 documents
Phage-borne factors and host LexA regulate the lytic switch in phage GIL01.
2011
ABSTRACT The Bacillus thuringiensis temperate phage GIL01 does not integrate into the host chromosome but exists stably as an independent linear replicon within the cell. Similar to that of the lambdoid prophages, the lytic cycle of GIL01 is induced as part of the cellular SOS response to DNA damage. However, no CI-like maintenance repressor has been detected in the phage genome, suggesting that GIL01 uses a novel mechanism to maintain lysogeny. To gain insights into the GIL01 regulatory circuit, we isolated and characterized a set of 17 clear plaque ( cp ) mutants that are unable to lysogenize. Two phage-encoded proteins, gp1 and gp7, are required for stable lysogen formation. Analysis of …
Elucidation of the regulation of an adult cuticle gene Acp65A by the transcription factor Broad.
2009
Broad (BR), an ecdysone-inducible transcription factor, is a major determinant of the pupal stage. The misexpression of BR-Z1 isoform (BR-Z1) during adult development of Drosophila melanogaster prevents the expression of the adult cuticle protein 65A gene (Acp65A). We found that the proximal 237 bp of the 5' flanking region of Acp65A were sufficient to mediate this suppression. A targeted point mutation of a putative BR-Z1 response element (BRE) within this region showed that it was not involved. Drosophila hormone receptor-like 38 (DHR38) is required for Acp65A expression. We found that BR-Z1 repressed DHR38 expression and that BR's inhibition of Acp65A expression was rescued by exogenous …
The diversity of GABAA receptors. Pharmacological and electrophysiological properties of GABAA channel subtypes.
1998
The amino acid gamma-aminobutyric-acid (GABA) prevails in the CNS as an inhibitory neurotransmitter that mediates most of its effects through fast GABA-gated Cl(-)-channels (GABAAR). Molecular biology uncovered the complex subunit architecture of this receptor channel, in which a pentameric assembly derived from five of at least 17 mammalian subunits, grouped in the six classes alpha, beta, gamma, delta, sigma and epsilon, permits a vast number of putative receptor isoforms. The subunit composition of a particular receptor determines the specific effects of allosterical modulators of the GABAARs like benzodiazepines (BZs), barbiturates, steroids, some convulsants, polyvalent cations, and et…
β1-Integrin Cytoplasmic Subdomains Involved in Dominant Negative Function
1998
The beta1-integrin cytoplasmic domain consists of a membrane proximal subdomain common to the four known isoforms ("common" region) and a distal subdomain specific for each isoform ("variable" region). To investigate in detail the role of these subdomains in integrin-dependent cellular functions, we used beta1A and beta1B isoforms as well as four mutants lacking the entire cytoplasmic domain (beta1TR), the variable region (beta1COM), or the common region (beta1 deltaCOM-B and beta1 deltaCOM-A). By expressing these constructs in Chinese hamster ovary and beta1 integrin-deficient GD25 cells (Wennerberg et al., J Cell Biol 132, 227-238, 1996), we show that beta1B, beta1COM, beta1 deltaCOM-B, a…
Claudin-18 gene structure, regulation, and expression is evolutionary conserved in mammals
2011
Claudin-18 isoform 2 (CLDN18.2) is one of the few members of the human claudin family of tight junction molecules with strict restriction to one cell lineage. The objective of the current study was to compare molecular structure and tissue distribution of this gastrocyte specific molecule in mammals. We show here that the CLDN18.2 protein sequence is highly conserved, in particular with regard to functionally relevant domains in mouse, rat, rabbit, dog, monkey and human and also in lizards. Moreover, promoter regions of orthologs are highly homologous, including the binding site of the transcription factor cyclic AMP-responsive element binding protein (CREB), which is known to regulate acti…
Hsp70 is required for optimal cell proliferation in mouse A6 mesoangioblast stem cells.
2009
Mouse Hsp70 (70 kDa heat shock protein) is preferentially induced by heat or stress stimuli. We previously found that Hsp70 is constitutively expressed in A6 mouse mesoangioblast stem cells, but its possible role in these cells and the control of its basal transcription remained unexplored. Here we report that in the absence of stress, Ku factor is able to bind the HSE (heat shock element) consensus sequence in vitro, and in vivo it is bound to the proximal hsp70 promoter. In addition, we show that constitutive hsp70 transcription depends on the co-operative interaction of different factors such as Sp1 (specificity protein 1) and GAGA-binding protein with Ku factor, which binds the HSE cons…
Experimental-Like Affinity Constants and Enantioselectivity Estimates from Flexible Docking
2012
Experimental-like affinity constants and enantioselectivity estimates, not predicted so far computationally, were obtained using a novel flexible modeling/docking combined strategy. The S- and R-warfarin-human serum albumin (HSA, site I) complexes were used as an interaction model. The process for a verified estimation includes the following: (i) ionized open chain forming at physiological pH (a recent focus); (ii) conformational search (molecular mechanics and Monte Carlo methods); (iii) rigid protein-flexible ligand docking (GlideXP) generating low energy paired S- and R-poses; (iv) graphical comparison against the X-ray crystal structure (unsatisfactory verification step); (v) quantum po…
Calcium binding and ionic conduction in single conical nanopores with polyacid chains: model and experiments.
2012
Calcium binding to fixed charge groups confined over nanoscale regions is relevant to ion equilibrium and transport in the ionic channels of the cell membranes and artificial nanopores. We present an experimental and theoretical description of the dissociation equilibrium and transport in a single conical nanopore functionalized with pH-sensitive carboxylic acid groups and phosphonic acid chains. Different phenomena are simultaneously present in this basic problem of physical and biophysical chemistry: (i) the divalent nature of the phosphonic acid groups fixed to the pore walls and the influence of the pH and calcium on the reversible dissociation equilibrium of these groups; (ii) the asym…
Baculoviral display of functional scFv and synthetic IgG-binding domains.
2000
Viral vectors displaying specific ligand binding moities such as scFv fragments or intact antibodies hold promise for the development of targeted gene therapy vectors. In this report we describe baculoviral vectors displaying either functional scFv fragments or the synthetic Z/ZZ IgG binding domain derived from protein A. Display on the baculovirus surface was achieved via fusion of the scFv fragment or Z/ZZ domain to the N-terminus of gp64, the major envelope protein of the Autographa californica nuclear polyhedrosis virus, AcNPV. As examples of scFv fragments we have used a murine scFv specific for the hapten 2-phenyloxazolone and a human scFv specific for carcinoembryonic antigen. In pri…
Glycosylation deficiency at either one of the two glycan attachment sites of cellular prion protein preserves susceptibility to bovine spongiform enc…
2004
The conversion into abnormally folded prion protein (PrP) plays a key role in prion diseases. PrP(C) carries two N-linked glycan chains at amino acid residues 180 and 196 (mouse). Previous in vitro data indicated that the conversion process may not require glycosylation of PrP. However, it is conceivable that these glycans function as intermolecular binding sites during the de novo infection of cells on susceptible organisms and/or play a role for the interaction of both PrP isoforms. Such receptor-like properties could contribute to the formation of specific prion strains. However, in earlier studies, mutations at the glycosylation sites of PrP led to intracellular trafficking abnormalitie…