Structure of Marek's disease virus DNA: detailed restriction enzyme map.

Purified virion DNA (120 X 10(6) molecular weight [MW]) of Marek's disease virus strain GA was cleaved with BamHI restriction endonuclease, and 27 out of the 29 fragments were cloned into bacterial plasmids. Restriction maps for BamHI, BglI, and SmaI endonucleases were constructed. The genomic structure of Marek's disease virus DNA was found to be similar to that of herpes simplex virus types 1 and 2. A long unique region (75 X 10(6) MW, located at 10 X 10(6) to 85 X 10(6) MW [10-85] from the left end of the genome), which was subdivided into segment 1 (22 X 10(6) MW, located at 10-32) and segment 2 (51 X 10(6) MW, located at 34-85) by direct repeats (32-34), was flanked by a long terminal region (10 X 10(6) MW, located at 0-10) and a long inverted region (10 X 10(6) MW, located at 85-95). A short unique region (8 X 10(6) MW, located at 103-111) was flanked by a short terminal region (8 X 10(6) MW, located at 111-119) and a short inverted region (8 X 10(6) MW, located at 95-103). The direct repeat fragments (0.9 X 10(6) could be isolated by cleavage with SmaI. The right terminal end was found to be heterogenous .