ICP27

ICP27 is a multifunctional protein encoded by the herpes simplex virus type 1 (HSV-1). It plays a crucial role in the viral replication cycle, acting as a key regulator of both viral and cellular gene expression. ICP27 is considered an essential viral protein, meaning that HSV-1 cannot replicate efficiently in its absence.

The primary function of ICP27 is to modulate host cell gene expression to favor viral replication. It achieves this through several mechanisms. One of its well-established roles is in the processing of viral RNAs. ICP27 can alter the normal splicing patterns of viral pre-mRNAs, leading to the production of specific viral transcripts required for later stages of infection. It also interferes with the export of cellular messenger RNAs (mRNAs) from the nucleus to the cytoplasm, effectively shutting down the production of many host proteins.

Furthermore, ICP27 interacts with a variety of cellular proteins, including transcription factors and splicing factors, thereby hijacking cellular machinery for viral purposes. It can also upregulate the expression of certain viral genes, including those encoding viral structural proteins, which are necessary for the assembly of new virions. The intricate regulatory activities of ICP27 highlight its central importance in the complex interplay between HSV-1 and its host cell.