A deletion analysis of hybrid phage carrying the US region of Herpes simplex virus type 1 (Patton). I. Isolation of deletion derivatives and identification of chi-likes sequences.

The EcoRI-H fragment (15.4 kb) of Herpes simplex virus type 1 (HSV-1) has been cloned in lambda gtWES in both orientations. This fragment contains the entire US region and has about 900 bp of terminal redundant sequences derived from the internal and terminal repeats of the S region. 56 independent plaque-forming deletion derivatives of the lambda gt/WES::EcoRI-H hybrid phage were isolated using either EDTA resistance or ability to grow on Escherichia coli(P2) lysogens as selective methods. The endpoints of these deletions were located using nine restriction enzymes that cleave within the EcoRI-H fragment. All of the deletions have at least one endpoint within the cloned fragment. Several unusual features of the lambda hybrids, including heterogeneity of a particular region in the HSV-1 EcoRI-H fragment and the presence of chi-like sequences in the US region of HSV-1, are discussed.