Suppression of transcription activity of the MEQ protein of oncogenic Marek's disease virus serotype 1 (MDV1) by L-MEQ of non-oncogenic MDV1.
Meq is one of the candidate oncogenes in the MDV1 genome. We previously reported a difference in the meq open reading frame (ORF) between oncogenic and non-oncogenic MDV1: L-meq, in which a 180-bp sequence is inserted into the meq ORF, is detected in non-oncogenic MDV1. To study the functions of a gene product of L-meq (L-MEQ), transactivation by L-MEQ was analyzed by dual luciferase assay using a reporter gene under the control of long (-1--873 bp) and short (-1 - -355 bp) meq promoter (LMP and SMP, respectively). LMP showed higher promoter function than SMP. L-MEQ transactivated the expression of the reporter gene, but less than MEQ did. In the presence of SMP or the cytomegalovirus immediate-early promoter, the same or slightly higher transactivation was observed in cells cotransfected with both meq and L-meq than cells transfected only with meq. However, in the presence of LMP, lower transactivation was observed in cells cotransfected with both meq and L-meq than cells transfected only with meq, suggesting that L-MEQ can be a transrepressor. Replication of a vvMDV1 was enhanced in the cells with meq. Interestingly, however, replication of vvMDV1 was suppressed in the cells with L-meq or with both L-meq and meq, compared to untransfected cells. Thus, L-MEQ could suppress replication of vvMDV1 displaying the meq gene in coinfected cells.
Chang
Kyung-Soo
KS
Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
Ohashi
Kazuhiko
K
Onuma
Misao
M
D000818:Animals; D000998:Antiviral Agents / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D015967:Gene Expression Regulation, Viral; D008381:Herpesvirus 2, Gallid / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D051379:Mice; D009856:Oncogene Proteins, Viral / Q000235:genetics* / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured; D014779:Virus Replication
D000998:Antiviral Agents; C100369:Eco-Q protein, Gallid herpesvirus 2; D009856:Oncogene Proteins, Viral