We used Northern hybridization to test whether destruction of the ORF-O, P ICP4-binding site affects LAT-encoded miRNA expression. R4530 expresses more miR-LAT-ICP34.5 (miR-H4-3p) than R4531 (its rescuant virus) in both Vero and SK-N-SH cells (Fig.3C), suggesting that ICP4 is involved in the regulation of miR-LAT-ICP34.5 (miR-H4-3p) expression in infected cells.