A POLYMORPHISM IN THE MAJOR IMMEDIATE-EARLY GENE DELINEATES GROUPS AMONG CYTOMEGALOVIRUS CLINICAL ISOLATES

Major immediate-early gene exon 4 sequences were determined at codons 161-241 and 254-397 in 25 cytomegalovirus clinical strains and compare d with those of reference strains AD169 and Towne. The nucleotide sequ ences at codon 161-241 segregated into three groups which could be det ermined by restriction mapping of a 247-nucleotide amplified target. A D169 and Towne belonged to the same group. Clustered variations and gr oup-specific amino-acid motifs found in the deduced peptide sequence o f the two immediate-early (IE) exon 4 regions raised a question as to the effects of polymorphism on IE1 function and/or immunogenicity. On the basis of restriction analysis of polymerase chain reaction (PCR) p roducts, virus isolates were also classified into four glycoprotein B (gB) genotypes. Strain distribution in IE1 and gB genotypes showed a l ack of concordance of the two grouping methods, and no preferential as sociation was observed between the clinical context or kind of specime n and IE1 or gB groups. These data lead up to further prospective stud ies which could provide important information on the implication of th e MIE gene region in virus pathogenesis and indicate whether linkage u nbalance exists in particular clinical contexts between IE1 and gB loc i. (C) 1998 Elsevier Science B.V. All rights reserved.