Sequence analysis of human cytomegalovirus US28 gene in low-passage clinical isolates from children and AIDS patients

摘要

Human cytomegalovirus (HCMV) is often a dangerousopportunistic pathogen that causes significant morbidityand mortality in newborn children and immunocompromisedpatients. The different symptoms and tissuetropisms of HCMV infection may result from geneticpolymorphism. This study investigated the sequencevariability of the HCMV US28 ORF, which shows sequencehomology to the G protein-coupled receptor.HCMV isolated from suspected pediatric cases and isolatesfrom AIDS patients were compared in order to examinethe possible associations between polymorphismsand pathogenesis. Seventy children with suspectedcongenital HCMV infection, who suffered from jaundice(47), megacolon (10), and microcephaly (13), and17 AIDS patients, were studied. Mutation was prevalentamong the sequences of US28, with a focus on the twoends of US28. The important functional groups of US28are highly conserved. An unrooted tree showed thatall sequences from suspected congenitally infected infantsand AIDS patients were divided into three groups.Comparison showed that most of the sequences (12/17)from pediatric patients were included in the first group(G1), whereas most of the sequences (11/17) from AIDSpatients were included in the third group (G3). The specifichigh mutation sites in US28 from children were locatedat the C terminus of the protein, whereas thosefrom AIDS patients were located at the N terminus. Wedemonstrated the existence of polymorphisms amongthe US28 genes of clinical isolates of HCMV from infantswith suspected congenital infection. Comparison of US28sequences from AIDS patients with those from childrenshowed that both sequences have their own specifichigh mutation points.