scholarly journals Spike protein homology between the SARS-associated virus and murine hepatitis virus implies existence of a putative receptor-binding region

2003 ◽  
Vol 48 (11) ◽  
pp. 1115-1117
Author(s):  
Yun Lu ◽  
Yinghua Chen
Keyword(s):  
Receptor Binding ◽  
Hepatitis Virus ◽  
Spike Protein ◽  
Protein Homology ◽  
Binding Region ◽  
Murine Hepatitis Virus ◽  
Putative Receptor ◽  
Receptor Binding Region

scholarly journals A Receptor-binding Region inEscherichia coliα-Haemolysin

2003 ◽  
Vol 278 (21) ◽  
pp. 19159-19163 ◽  
Author(s):  
Aitziber L. Cortajarena ◽  
Félix M. Goñi ◽  
Helena Ostolaza
Keyword(s):  
Receptor Binding ◽  
Binding Region ◽  
Receptor Binding Region

scholarly journals Variations in Disparate Regions of the Murine Coronavirus Spike Protein Impact the Initiation of Membrane Fusion

2001 ◽  
Vol 75 (6) ◽  
pp. 2792-2802 ◽  
Author(s):  
Dawn K. Krueger ◽  
Sean M. Kelly ◽  
Daniel N. Lewicki ◽  
Rosanna Ruffolo ◽  
Thomas M. Gallagher
Keyword(s):  
Tissue Culture ◽  
Membrane Fusion ◽  
Cultured Cells ◽  
Hepatitis Virus ◽  
Fusion Reaction ◽  
Spike Protein ◽  
Soluble Form ◽  
Fusion Activity ◽  
Murine Hepatitis Virus

ABSTRACT The prototype JHM strain of murine hepatitis virus (MHV) is an enveloped, RNA-containing coronavirus that has been selected in vivo for extreme neurovirulence. This virus encodes spike (S) glycoproteins that are extraordinarily effective mediators of intercellular membrane fusion, unique in their ability to initiate fusion even without prior interaction with the primary MHV receptor, a murine carcinoembryonic antigen-related cell adhesion molecule (CEACAM). In considering the possible role of this hyperactive membrane fusion activity in neurovirulence, we discovered that the growth of JHM in tissue culture selected for variants that had lost murine CEACAM-independent fusion activity. Among the collection of variants, mutations were identified in regions encoding both the receptor-binding (S1) and fusion-inducing (S2) subunits of the spike protein. Each mutation was separately introduced into cDNA encoding the prototype JHM spike, and the set of cDNAs was expressed using vaccinia virus vectors. The variant spikes were similar to that of JHM in their assembly into oligomers, their proteolysis into S1 and S2 cleavage products, their transport to cell surfaces, and their affinity for a soluble form of murine CEACAM. However, these tissue culture-adapted spikes were significantly stabilized as S1-S2 heteromers, and their entirely CEACAM-dependent fusion activity was delayed or reduced relative to prototype JHM spikes. The mutations that we have identified therefore point to regions of the S protein that specifically regulate the membrane fusion reaction. We suggest that cultured cells, unlike certain in vivo environments, select for S proteins with delayed, CEACAM-dependent fusion activities that may increase the likelihood of virus internalization prior to the irreversible uncoating process.

The Galactosyl Ceramide/Sulfatide Receptor Binding Region of HIV-1 gp120 Maps to Amino Acids 206-275

1993 ◽  
Vol 9 (2) ◽  
pp. 175-181 ◽  
Author(s):  
SHAMA BHAT ◽  
RICHARD V. METTUS ◽  
E. PREMKUMAR REDDY ◽  
K.E. UGEN ◽  
V. SRIKANTHAN ◽  
...  
Keyword(s):  
Amino Acids ◽  
Receptor Binding ◽  
Binding Region ◽  
Galactosyl Ceramide ◽  
Receptor Binding Region ◽  
Hiv 1

Characterization of a complex glucocorticoid response unit in the phosphoenolpyruvate carboxykinase gene

1990 ◽  
Vol 10 (9) ◽  
pp. 4712-4719
Author(s):  
E Imai ◽  
P E Stromstedt ◽  
P G Quinn ◽  
J Carlstedt-Duke ◽  
J A Gustafsson ◽  
...  
Keyword(s):  
Glucocorticoid Receptor ◽  
Receptor Binding ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Binding Region ◽  
Factor Binding ◽  
Response Unit ◽  
Accessory Factor ◽  
Glucocorticoid Response ◽  
Glucocorticoid Induction ◽  
Receptor Binding Region

The minimal DNA sequence required for glucocorticoid induction of the phosphoenolpyruvate carboxykinase (PEPCK) gene in H4IIE rat hepatoma cells was defined. This novel glucocorticoid response unit (GRU) spans about 110 base pairs (bp) and includes two receptor-binding elements plus two accessory factor-binding elements. Purified glucocorticoid receptor bound to two regions (GR1 and GR2) between -395 and -349 bp relative to the transcription start site. Factors in crude rat liver nuclear extract bound to DNA in the regions -455 to -431 and -420 to -403 bp, which are designated accessory factor 1 (AF1) and accessory factor 2 (AF2) elements, respectively. Gel retardation analysis revealed that at least two proteins bound to AF1 and that they were distinct from the protein(s) that bound to AF2. Various combinations of GR1, GR2, AF1, and AF2 were fused to the chloramphenicol acetyltransferase (CAT) reporter gene and cotransfected with a glucocorticoid receptor expression plasmid (pSVGR1) into H4IIE cells to identify the functional GRU. Neither the glucocorticoid receptor binding region nor the accessory factor binding region alone was sufficient to confer glucocorticoid responsiveness. The two components of the glucocorticoid receptor binding region functioned independently, and each accounted for half of the maximal response, provided the accessory factor elements were present. Similarly, deletion of either AF1 or AF2 diminished glucocorticoid induction of the PEPCK gene to approximately half of the maximum. We propose that the complex PEPCK gene GRU provides the stringent regulation required of this critical enzyme in liver.

scholarly journals Expression of Hemagglutinin Esterase Protein from Recombinant Mouse Hepatitis Virus Enhances Neurovirulence

2005 ◽  
Vol 79 (24) ◽  
pp. 15064-15073 ◽  
Author(s):  
Lubna Kazi ◽  
Arjen Lissenberg ◽  
Richard Watson ◽  
Raoul J. de Groot ◽  
Susan R. Weiss
Keyword(s):  
Receptor Binding ◽  
Demyelinating Disease ◽  
Hepatitis Virus ◽  
Critical Role ◽  
Spike Glycoprotein ◽  
Murine Hepatitis Virus ◽  
Recombinant Viruses ◽  
Viral Spread ◽  
The Central Nervous System

ABSTRACT Murine hepatitis virus (MHV) infection provides a model system for the study of hepatitis, acute encephalitis, and chronic demyelinating disease. The spike glycoprotein, S, which mediates receptor binding and membrane fusion, plays a critical role in MHV pathogenesis. However, viral proteins other than S also contribute to pathogenicity. The JHM strain of MHV is highly neurovirulent and expresses a second spike glycoprotein, the hemagglutinin esterase (HE), which is not produced by MHV-A59, a hepatotropic but only mildly neurovirulent strain. To investigate a possible role for HE in MHV-induced neurovirulence, isogenic recombinant MHV-A59 viruses were generated that produced either (i) the wild-type protein, (ii) an enzymatically inactive HE protein, or (iii) no HE at all (A. Lissenberg, M. M. Vrolijk, A. L. W. van Vliet, M. A. Langereis, J. D. F. de Groot-Mijnes, P. J. M. Rottier, and R. J. de Groot, J. Virol. 79:15054-15063, 2005 [accompanying paper]). A second, mirror set of recombinant viruses was constructed in which, in addition, the MHV-A59 S gene had been replaced with that from MHV-JHM. The expression of HE in combination with A59 S did not affect the tropism, pathogenicity, or spread of the virus in vivo. However, in combination with JHM S, the expression of HE, regardless of whether it retained esterase activity or not, resulted in increased viral spread within the central nervous system and in increased neurovirulence. Our findings suggest that the properties of S receptor utilization and/or fusogenicity mainly determine organ and host cell tropism but that HE enhances the efficiency of infection and promotes viral dissemination, at least in some tissues, presumably by serving as a second receptor-binding protein.

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