Complete nucleotide sequence of the mycoplasma virus P1 genome

Mycoplasma virus P1 is one of only four viruses isolated from the genus Myc oplasma. The host for P1. Mycoplasma pulmonis, possesses complex, phase-var iable restriction and modification enzymes and the Vsa family of phase-vari able surface proteins. The ability of PI virus to infect host cells is infl uenced by these phase-variable systems, rendering P1 a valuable tool for as sessing host properties. The double-stranded PI DNA genome was sequenced (1 1,660 bp) and ii ORFs were identified. The predicted PI DNA polymerase is s imilar to that of phages that ate known to have terminal protein (TP) attac hed to the 5' end of their genome, consistent with previous studies indicat ing that PI DNA has covalently attached TP Most of the other predicted P1 p roteins have little sequence similarity to known proteins, and P1 virus is unrelated to the other mycoplasma virus, MAV1, for which the genome sequenc e is known. One of the predicted P1 proteins, the ORF 8 gene product, conta ins a repetitive collagen-like motif characteristic of some bacteriophage: tail Aber proteins and is a candidate for interacting with the Vsa proteins . (C) 2001 Academic Press.