The Functions and Activities of Herpes Simplex Virus Protein ICP27, a Multifunctional Regulator of Gene Expression
Rozanne M. Sandri-Goldin
from: Alpha Herpesviruses: Molecular and Cellular Biology (Edited by: R. M. Sandri-Goldin). Caister Academic Press, U.K. (2006)
ICP27 is a multifunctional regulator of gene expression that assumes different roles throughout the course of infection. At early times, ICP27 is an inhibitor of cellular splicing, whereas, at later times it is involved in recruiting RNA polymerase II to viral sites of replication and in facilitating viral RNA export. Evidence also suggests that at late times, it may be involved in the stimulation of translation of viral transcripts. ICP27 performs its activities by interacting with RNA and with a myriad of proteins. ICP27 binds viral RNAs to facilitate their export. Further, ICP27 interacts with itself to form multimers, and with HSV-1 proteins ICP4 and ICP8, as well as with an increasing number of cellular proteins. The regions of ICP27 involved in these interactions have been broadly mapped to both the N-terminal and C-terminal halves of the molecule. Several protein motifs have been identified based upon sequence comparisons; however, no structural information has yet been generated. Although much has been learned about the mechanisms by which ICP27 performs its roles, little is known about how its varied activities are regulated. The roles and activities of ICP27 are detailed in this review read more ...