Identification and characterization of Marek's disease virus serotype 1 (MDV1) ICP22 gene product: MDV1 ICP22 transactivates the MDV1 ICP27 promoter synergistically with MDV1 ICP4.
A previous report [Virus Genes 6 (1992) 365-378] has shown that the US1 gene of Marek's disease virus serotype 1 (MDV1) encodes a homologue of herpes simplex virus type 1 infected cell protein No. 22 (ICP22). In the present study, we expressed and identified a product of the MDV1 US1 gene in chicken embryo fibroblasts (CEFs) with the aid of a recombinant baculovirus expressing a Flag epitope-tagged MDV1 US1 gene, under control of the SRalpha promoter (composed of the enhancer region of the simian virus 40 early promoter and the R region of the human T-cell leukaemia virus type 1 long terminal repeat). In CEF infected with the recombinant baculovirus, MDV1 ICP22 was specifically and efficiently expressed in the presence of n-butyric acid. The apparent M(r) of the expressed protein was 30,000. Reporter gene assays revealed that MDV1 ICP22 by itself transactivated an MDV1 ICP27 promoter/reporter construct weakly but specifically, and furthermore, worked synergistically with MDV1 ICP4 to efficiently up-regulate the MDV1 ICP27 promoter. MDV1 ICP22 may be a regulatory protein that stimulates viral promoters in co-operation with other viral regulatory proteins such as MDV1 ICP4.
Kato
Kentaro
K
Department of Tumor Virology, Division of Virology and Immunology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan.
Izumiya
Yoshihiro
Y
Tohya
Yukinobu
Y
Takahashi
Eiji
E
Hirai
Kanji
K
Kawaguchi
Yasushi
Y
D000818:Animals; D016367:Baculoviridae / Q000235:genetics; D019556:COS Cells; D002642:Chick Embryo; D002645:Chickens; D005347:Fibroblasts; D015967:Gene Expression Regulation, Viral / Q000235:genetics; D005809:Genes, Regulator / Q000502:physiology; D008381:Herpesvirus 2, Gallid / Q000235:genetics* / Q000378:metabolism; D017874:Immediate-Early Proteins / Q000235:genetics* / Q000378:metabolism; D008380:Marek Disease / Q000276:immunology* / Q000821:virology; D009842:Oligopeptides; D010455:Peptides / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation; D015854:Up-Regulation; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins
C057294:ICP22 protein, human herpesvirus 1; D017874:Immediate-Early Proteins; D009842:Oligopeptides; D010455:Peptides; D011994:Recombinant Proteins; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C078424:EUS1 protein, Equine herpesvirus 1; C085706:FLAG peptide