Pl. Ward et al., Identification of a novel expressed open reading frame situated between genes U(L)20 and U(L)21 of the herpes simplex virus 1 genome, VIROLOGY, 266(2), 2000, pp. 275-285
An open reading frame (ORF) situated between the U(L)20 and U(L)21 genes en
codes a protein designated as U(L)20.5. The U(L)20.5 ORF lies 5' and in the
same orientation as the U(L)20 ORF. The expression of the U(L)20.5 ORF was
verified by RNase protection assays and by in-frame insertion of an amino
acid sequence encoding an epitope of an available monoclonal antibody. The
tagged U(L)20.5 protein colocalized in small dense nuclear structures with
products of the alpha 22/U(s)1.5, U(L)3, and U(L)4 genes. Expression of the
U(L)20.5 gene was blocked in cells infected and maintained in the presence
of phosphonoacetate, indicating that it belongs to the late, or gamma(2),
kinetic class. U(L)20.5 is not essential for viral replication inasmuch as
a recombinant virus made by insertion of the thymidine kinase gene into the
U(L)20.5 ORF replicates in all cell lines tested [J. D. Baines, P. L. Ward
, G. Campadelli-Fiume, and B. Roizman (1991) J. Virol. 65, 6414-6424]. The
genomic location of the recently discovered genes illustrates the compact n
ature of the viral genome. (C) 2000 Academic Press.