Human cytomegalovirus RL13 gene transcripts in a clinical strain.

Human cytomegalovirus (HCMV) RL13 gene is a member of the RL11 gene family. To study the expression kinetics and transcript structures of the gene, screening of cDNA library, Northern blot, 3' and 5' RACE analyses were performed with a low-passaged clinical strain. The results showed that the RL13 gene was mainly transcribed in the late expression phase with at least seven forms of transcripts of 3628, 3114, 2515-2443, 1737, 1240, 1029 and 846 nt, respectively. All these transcripts were unspliced with an identical 3' terminal and the same typical polyA signal "AATAAA". Except for the transcript of 846 nt, RL13 open reading frames (ORFs) were 909 bp and completely identical in all of the transcripts. The sequence of the RL13 ORF in the examined clinical strain had a higher similarity with that of the UL153 ORF in the Towne strain than those of RL13 ORF in any other HCMV strains.