TY - JOUR
T1 - Identification of the human cytomegalovirus G protein-coupled receptor homologue encoded by UL33 in infected cells and enveloped virus particles
AU - Margulies, Barry J.
AU - Browne, Helena
AU - Gibson, Wade
N1 - Funding Information:
We thank Jenny Borchelt and Rebecca Magno for their excellent technical assistance and James Hildreth for help in preparing the rabbit F(ab)2 anti-33 fragments. We also thank Phil Murphy, Frank Kolakowski, Terri Attwood, and John Nicholas for helpful discussions on GCR homology. John Nicholas also provided the protein sequences of the HHV-7 GCR homologues. B.J.M. was a student in the Biochemistry, Cellular, and Molecular Biology Training Program and was supported, in part, by Grant GM07445 from USPHS; H.B. is a postdoctoral fellow in the laboratory of Tony Minson. This work was supported in part by USPHS Grants AI13718 and AI22711 to W.G. and by Wellcome Trust UK grants to Tony Minson, in whose lab the D33 mutant was made.
PY - 1996/11/1
Y1 - 1996/11/1
N2 - Human cytomegalovirus (HCMV), strain AD169, contains four genes (US27, US28, UL33, and UL78) that encode putative homologues of cellular G protein-coupled receptors (GCRs). GCRs transduce extracellular signals to alter intracellular processes, and there is evidence that HCMV may elicit such changes at early times following infection. The US27, US28, and UL33 genes are transcribed during infection, and the US28 gene product has been found to be a functional receptor for the β-chemokine class of immune modulators. The US27, UL33, and UL78 gene products have not been described and we have concentrated on identifying the UL33 protein because it is the most highly conserved of the GCR homologues among the human β and γ herpesviruses. We report here cloning UL33 into a recombinant baculovirus (rBV) and expressing it in insect cells; constructing a mutant HCMV with a disrupted UL33 gene; and identifying the UL33 protein in HCMV-infected cells and virus particles. Our results demonstrate that the UL33 protein (i) is expressed as a ~36-kDa, heat aggregatable protein in rBV-infected cells, (ii) is modified heterogeneously by asparagine-linked glycosylation and expressed as a ≤58-kDa glycoprotein that is present in the region of the cytoplasmic inclusions in HCMV-infected fibroblasts, (iii) is present in virions and two other enveloped virus particles, and (iv) is not essential for growth of HCMV in human foreskin fibroblast cultures.
AB - Human cytomegalovirus (HCMV), strain AD169, contains four genes (US27, US28, UL33, and UL78) that encode putative homologues of cellular G protein-coupled receptors (GCRs). GCRs transduce extracellular signals to alter intracellular processes, and there is evidence that HCMV may elicit such changes at early times following infection. The US27, US28, and UL33 genes are transcribed during infection, and the US28 gene product has been found to be a functional receptor for the β-chemokine class of immune modulators. The US27, UL33, and UL78 gene products have not been described and we have concentrated on identifying the UL33 protein because it is the most highly conserved of the GCR homologues among the human β and γ herpesviruses. We report here cloning UL33 into a recombinant baculovirus (rBV) and expressing it in insect cells; constructing a mutant HCMV with a disrupted UL33 gene; and identifying the UL33 protein in HCMV-infected cells and virus particles. Our results demonstrate that the UL33 protein (i) is expressed as a ~36-kDa, heat aggregatable protein in rBV-infected cells, (ii) is modified heterogeneously by asparagine-linked glycosylation and expressed as a ≤58-kDa glycoprotein that is present in the region of the cytoplasmic inclusions in HCMV-infected fibroblasts, (iii) is present in virions and two other enveloped virus particles, and (iv) is not essential for growth of HCMV in human foreskin fibroblast cultures.
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U2 - 10.1006/viro.1996.0579
DO - 10.1006/viro.1996.0579
M3 - Article
C2 - 8918538
AN - SCOPUS:0030297309
SN - 0042-6822
VL - 225
SP - 111
EP - 125
JO - Virology
JF - Virology
IS - 1
ER -