Difference in virus-binding activity of two distinct receptor proteins for mouse hepatitis virus.
The receptor proteins, MHVR1 (Bgp C or splice variant of mmCGM1 containing two ectodomains) and MHVR2 (mmCGM2) have been reported to be functional receptors for MHV, although there was a significant difference in their virus-binding activity as determined by virus overlay protein blot assay (VOPBA). To compare the receptor function of these proteins, their virus-binding capacities were tested by using soluble forms of the proteins which lacked the transmembrane and intracytoplasmic domains. To estimate the amounts of these proteins expressed, an epitope of influenza HA protein, for which specific monoclonal antibody was available, was used as a tag. Recombinant soluble MHVR1 and MHVR2, expressed in RK 13 cells using recombinant vaccinia virus were secreted into the culture fluids of infected cells expressing these proteins. The inhibitory effect on virus infectivity of MHVR1 was shown to be about 500-fold higher than that of MHVR2. A similar disparity was observed in virus binding by VOPBA. These two proteins worked as functional receptors when they were expressed on resistant BHK-21 cells. However, the efficiency of MHV infection in BHK-21 cells expressing MHVR1 was about 30-fold higher, as compared with those expressing MHVR2. These data show that the receptor function of MHVR1 was significantly higher than that of MHVR2 and suggests that the difference in susceptibility between SJL and BALB/c mice might be due to the specific receptor protein expressed in those animals.
Ohtsuka
N
N
National Institute of Neuroscience, NCNP, Tokyo, Japan.
Yamada
Y K
YK
Taguchi
F
F
D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD; D001483:Base Sequence; D002272:Carcinoembryonic Antigen; D015815:Cell Adhesion Molecules; D002460:Cell Line; D006224:Cricetinae; D017931:DNA Primers; D015870:Gene Expression; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D006517:Murine hepatitis virus / Q000378:metabolism*; D011991:Receptors, Virus / Q000235:genetics / Q000378:metabolism*
D015703:Antigens, CD; C069847:CD66 antigens; D002272:Carcinoembryonic Antigen; C486183:Ceacam1 protein, mouse; C087701:Ceacam2 protein, mouse; D015815:Cell Adhesion Molecules; D017931:DNA Primers; D006023:Glycoproteins; D011991:Receptors, Virus