Characterization of the transcripts of human cytomegalovirus UL144

Rong He,Ning Wang,Yaohua Ji,Zhengrong Sun,Mali Li,Yanping Ma,Qiang Ruan,Ying Qi,Shujuan Jiang

doi:10.1186/1743-422x-8-299

Abstract

BackgroundThe genome of human cytomegalovirus (HCMV) has been studied extensively, particularly in the UL/b' region. In this study, transcripts of one of the UL/b' genes, UL144, were identified in 3 HCMV isolates obtained from urine samples of congenitally infected infants.MethodsNorthern blot hybridization, cDNA library screening, and RACE-PCR were used.ResultsWe identified at least 4 differentially regulated 3'-coterminal transcripts of UL144 in infected cells of 1,300, 1,600, 1,700, and 3,500 nucleotides (nt). The 1600 nt transcript was the major form of UL144 mRNA. The largest transcript initiated from the region within the UL141 open reading frame (ORF) and included UL141, UL142, UL143, UL144, and UL145 ORFs.ConclusionsThese findings reveal the complex nature of the transcription of the UL144 gene in clinical isolates.

Highlights

The genome of human cytomegalovirus (HCMV) has been studied extensively, in the UL/b’ region
Identification of UL144 transcripts by cDNA library screening Twenty-two distinct clones were identified from the cDNA library and all were sequenced successfully
The 5’ end of the 2500 bp product occurred at nt 9,303, which is located within the UL141 open reading frame (ORF)

Summary

Introduction

The genome of human cytomegalovirus (HCMV) has been studied extensively, in the UL/b’ region. Transcripts of one of the UL/b’ genes, UL144, were identified in 3 HCMV isolates obtained from urine samples of congenitally infected infants. Human cytomegalovirus (HCMV) is a common cause of congenital viral infections and a frequent opportunistic pathogen in transplant recipients and AIDS patients [1,2,3]. The relative genomic complexity of HCMV is mirrored by its biological characteristics, as the most relevant cellular reservoirs of the latent virus and its sites for permissive replication have not been conclusively established and its pathogenesis is not well understood. Like other CMVs, HCMV has a very specific host range, but within a permissive host it enters and replicates in a wide variety of cell types [3,4]. The sequences of specific ORFs can be highly variable, including RL6, RL12, UL4, UL18, UL55 (gB), UL73 (gN), UL74 (gO), UL139, UL144, and UL146 [5,9,10,11,12,13,14,15,16,17,18]

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