Posttranscriptional Regulation in Herpes Simplex Virus

Abstract

The essential herpes simplex virus type 1 (HSV-1) immediate-early protein IE63 (ICP27) is an RNA binding protein which, at the posttranscriptional level, interacts with cellular splicing small nuclear ribonucleoprotein particles (snRNPs) and inhibits RNA splicing, promotes RNA 3′ processing, and prevents the nucleocytoplasmic transport of intron-containing mRNAs. IE63 is the only HSV IE protein with homologs not only among other α herpesviruses, but also throughout the herpesviridae family. Recent evidence shows that IE63 is a nucleocytoplasmic shuttle protein able to travel from snRNP- and RNA-rich nuclear foci to the cytoplasm. This property suggests that IE63 may facilitate the nuclear export of virus mRNAs, perhaps selectively, of HSV-1 transcripts, from virus genes which lack introns. Posttranscriptional effects of other HSV-1 functions are discussed.