Expression and in vitro Characterization of Herpes Simplex Virus 1 (HSV-1) ORF P Protein

Herpes simplex virus 1 (HSV-1) unspliced 8.3 latency associated transcript (LAT), which located in the long repeat sequences, has been shown to contain at least 16 open reading frames (ORF: A-P). One of these ORF, ORF P, maps almost entirely antisense to HSV-1 neurovirulence gene, ICP34.5. Both ORF P and ICP34.5 are located in the long repeat and are antisense overlapping genes. Therefore, in ORF P deletion mutants, ICP34.5 is also deleted and thus, the characterization of ORF P mutants is almost impossible. An alternative way to analyse its function is to determine those cellular and viral proteins which interact with ORF P. During these experiments, firstly, the expression of full length GlutationeS-transferase (GST)-ORF P fusion protein was optimised and then, using GST-pull down, it was shown that ORF P interacts with a viral and a few cellular proteins in vitro. Conclusively, ORF P might have some functions in HSV-1 replication cycle.