Rh. Smith et al., NUCLEAR-LOCALIZATION AND TRANSCRIPTIONAL ACTIVATION ACTIVITIES OF TRUNCATED VERSIONS OF THE IMMEDIATE-EARLY GENE-PRODUCT OF EQUINE HERPESVIRUS-1, Journal of virology, 69(6), 1995, pp. 3857-3862
The equine herpesvirus 1 (EHV-1) immediate-early (IE) gene product enc
odes a nuclear regulatory protein capable of negatively autoregulating
its own promoter, transactivating representative EHV-1 early promoter
s, and acting in a concerted fashion with accessory EHV-1 regulatory f
actors to transactivate EHV-1 late promoters. To identify IE amino aci
d sequences involved in nuclear localization and to examine the contri
bution of C-terminal portions of the IE polypeptide to transactivation
, vectors that express various carboxy-terminally truncated IE polypep
tides were constructed. It is demonstrated that amino acids 963 throug
h 970 of the 1,487-amino-acid IE protein are required for efficient lo
calization of the truncated IE polypeptides to the nuclei of transfect
ed cells. In addition, it is demonstrated that the first 970 amino aci
ds of the IE gene product are sufficient to transactivate the EHV-1 th
ymidine kinase promoter to significant levels (i.e., approximately 40%
of the level of wild-type activation).