[Variability of human cytomegalovirus UL144 gene in low-passage clinical isolates analyzed by HMA-SSCP]

Human cytomegalovirus (HCMV) infection is an important infectious agent that results in neonatal disease and congenital deformity. HCMV infection may affect in many organs. The different symptoms and tissue tropism of HCMV infection perhaps resulted from the genetic polymorphism of HCMV. HCMV UL144 open reading frames encode a homologue of the tumor necrosis factor receptor. It seems important to study the strain-specific variability of UL144 sequence in low-passage clinical isolates and to discuss if the variability related to the clinical HCMV infection.

HCMV-UL144 gene was amplified by PCR assay in 65 low-passage clinical isolates and urine from 7 healthy children who were HCMV-DNA positive by quantitative PCR. All the positive PCR products were analyzed by Heteroduplex mobility assay and single-stranded conformation polymorphism (HMA-SSCP) and 32 of them were sequenced.

Fifty-five isolates and 5 urine specimens were HCMV-UL144 positive by PCR. Sequencing and HMA-SSCP analysis showed that significant strain-specific variability was present in the UL144 ORFs. Comparing UL144 sequences and the corresponding symptoms showed that genotype 2 did not exist in megacolon isolates. And genotype 1 and 3 were the major types among microcephaly and jaundice isolates respectively.

HCMV-UL144 existed in almost all the low passage isolates. HMA-SSCP assay is an easy and effective method to detect the genetype of HCMV-UL144 sequence. The characteristic of sequences in different isolates showed that UL144 gene may play an important role in HCMV infection.