SEQUENCE VARIATION WITHIN 3 IMPORTANT CYTOMEGALOVIRUS GENE REGIONS INISOLATES FROM 4 DIFFERENT PATIENT POPULATIONS

We determined the nucleotide (nt) and amino acid (aa) heterogeneities of three distinct regions of the human cytomegalovirus (CMV) genome fo r 46 low-passage CMV isolates from four different patient populations (congenitally infected infants, children attending day care centers, r enal transplant recipients, and human immunodeficiency virus-infected individuals) and for two laboratory strains (CMV Ad169 and Towne). The gene regions for the major immediate-early (MIE) exon 4 gene (nt posi tions 1702 to 1982, aa positions 152 to 244), the DNA polymerase gene (nt positions 2797 to 3046, aa positions 713 to 795), and the glycopro tein B (gB) gene (nt positions 1698 to 1884, aa positions 567 to 628) were sequenced, The sequence information was used to design sets of ne sted PCR primers directed against the most highly conserved regions id entified, MIE was the most variable gene region compared to the variab ility of the DNA polymerase and gB gene regions. Comparison of the seq uences of all 46 isolates with that of Ad169 revealed nt and aa sequen ce homologies of 87.9 and 87.2%, respectively, within the MIE gene com pared to 92.8 and 100% homologies, respectively, within the DNA polyme rase gene and 93 and 95.2% homologies, respectively, within the gB gen e. Within the MIE gene, compared to the Ad169 nt sequence the homology at the nt level among isolates obtained front children attending day- care centers was high (96.4%), while it was lower (90%) among isolates obtained from the other three patient populations. Preliminary result s of a nested PCR with oligonucleotide primers selected from the DNA p olymerase gene region with a low level of nt sequence variation indica tes that primers selected from this region might be more powerful for use in FCR than primers selected from the MIE gene region.