title: Sequence and organization of the genomic termini of equine herpesvirus type 1.
abstract: The nucleotide sequence and organization of the genomic termini and of the junction of the long (L) and short (S) regions of the equine herpesvirus type 1 genome were determined. Sequencing of the XbaI-Q fragment (1441 nucleotides) revealed that the left terminus contains sets of inverted repeat and direct repeat sequences. The terminal sequence is described as DR1-UC-DR4 (18, 60, and 16 nucleotides, respectively) because of its homology to these elements of the 'a' sequence of herpes simplex virus. Located at each terminus of the S region as part of the inverted repeats is a 54 nucleotide sequence with homology to the Ub element of the HSV 'a' sequence. Thus, these data suggest that fusion of the EHV-1 genomic termini during replication will generate a sequence equivalent to Ub-DR1-Uc-DR4, which is known to be an ideal cleavage/packaging signal in herpesviral DNAs. Eighty-seven nucleotides of the L region left terminus sequence are repeated in an inverted fashion at nucleotide 892; also a 32 basepair portion, DR1-Uc (18 and 14 basepairs respectively), is reiterated 20 times in an inverted fashion as part of a 54 basepair tandem repeat located at the other L region terminus (L-S junction). It is not known whether these small inverted repeats at the L termini mediate isomerization of the L region at a very low level. The organization of the terminal sequences of the EHV-1 genome and the similarity of these sequences to the cleavage/packaging elements of other herpesviruses are discussed.
authors.affiliation: Department of Microbiology and Immunology, Louisiana State University Medical Center, Shreveport 71130-3932.
authors.forename: R R
authors.initials: RR
authors.lastname: Yalamanchili
authors.forename: D J
authors.initials: DJ
authors.lastname: O'Callaghan
mesh_terms: D001483:Base Sequence; D005814:Genes, Viral; D006564:Herpesviridae / Q000235:genetics*; D004861:Herpesvirus 1, Equid / Q000235:genetics*; D008969:Molecular Sequence Data; D012091:Repetitive Sequences, Nucleic Acid; D012689:Sequence Homology, Nucleic Acid; D018139:Simplexvirus / Q000235:genetics