The product of human cytomegalovirus UL73 is a new polymorphic structural glycoprotein (gpUL73).
OBJECTIVE
This work focuses on human cytomegalovirus (HCMV) UL73, which encodes for a putative transmembrane glycoprotein that is highly conserved among herpesviruses.


METHODS
pUL73 expression was analyzed both in transiently transfected and in HCMV-infected cells using a pUL73-specific antiserum by immunoblot and immunofluorescence. Sequencing analysis from several clinical isolates and laboratory-adapted strains was also performed.


RESULTS
pUL73 expressed in transiently transfected cells consists in a polypeptide of the expected size (15-18 kd) with cytoplasmic localization. In infected cells, pUL73 is expressed with true-late kinetics and localizes both in perinuclear granular formations and on the cell surface. A broad band (39-53 kd), sensitive to O-glycosidase digestion was detected in purified virus. In addition, sequence analysis showed that the N-terminal portion of pUL73 from clinical isolates is highly polymorphic.


CONCLUSIONS
UL73 encodes for a new structural glycoprotein (gpUL73) expressed on the cell surface of infected cells and highly polymorphic among clinical isolates.
Dal Monte
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Department of Clinical and Experimental Medicine, University of Bologna, Italy. dalmonte@med.unibo.it
Pignatelli
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Mach
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Landini
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MP
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002522:Chlorocebus aethiops; D003587:Cytomegalovirus / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D003586:Cytomegalovirus Infections / Q000821:virology; D004279:DNA, Viral; D015870:Gene Expression; D006023:Glycoproteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting / Q000379:methods; D008969:Molecular Sequence Data; D009842:Oligopeptides; D016366:Open Reading Frames; D010455:Peptides / Q000235:genetics; D011110:Polymorphism, Genetic; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions; D014759:Viral Envelope Proteins / Q000235:genetics* / Q000378:metabolism; D015678:Viral Structural Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism
D004279:DNA, Viral; D006023:Glycoproteins; D009842:Oligopeptides; D010455:Peptides; D011993:Recombinant Fusion Proteins; D014759:Viral Envelope Proteins; D015678:Viral Structural Proteins; C417883:glycoprotein N, Human cytomegalovirus; C085706:FLAG peptide