Immediate-early polypeptides of herpes simplex virus type 2 infected cells

Herpes simplex virus type 2 infected cells produce virus-specific polypeptides in three coordinately controlled kinetic classes. The immediate early (α) class of infected cell polypeptides is thought to be functionally important to the HSV-2 polypeptide synthesis control mechanism. The α polypeptides (ICP4, ICPO, and ICP27) have been purified by high resolution preparative polyacrylamide gel electrophoresis containing sodium dodecyl sulfate. Monospecific antisera have been produced against these highly purified proteins and used as immunologic probes to characterize their intracellular expression in HSV-2 infected cells. Antisera produced against two of the α polypeptides (ICP4 and ICP27) have been shown by indirect immunofluorescence to react equally with herpes simplex virus type-1 (HSV-1) and HSV-2 infected cells. The antiserum produced against the ICP0 α polypeptide, however, reacted only with HSV-2 infected cells. The times of appearance and intracellular migration of the a polypeptides have also been examined by immunofluorescence, and it was found that: 1) ICP4 migrates to the nucleus of HSV-2 infected cells where its presence is detectable through 10 hours post infection (hrs pi); 2) ICPO migrates to the nucleus of HSV-2 infected cells but is only detectable during the first six hours of infection; and 3) ICP27 is expressed in the cytoplasm of HSV-2 infected cells from three through ten hrs pi. The times of appearance and intracellular migration of the α polypeptides have also been examined in HSV-2 infected cells cultured in the presence of amino acid analogues (canavanine and azetidine) which are known to alter the control mechanism of HSV-2 polypeptide synthesis. The times of appearance and intracellular location of HSV-2 infected cell polypeptides cultured in the presence or absence of amino acid analogues have been used to propose a model of HSV-2 polypeptide synthesis control which implicates the α polypeptides in the induction or maintenance of the HSV-2 lytic cycle and the latent state.