Identification of an immediate-early gene in the Marek's disease virus long internal repeat region which encodes a unique 14-kilodalton polypeptide.

AUTOR(ES)

Hong, Y

RESUMO

Marek's disease virus (MDV) is an oncogenic avian herpesvirus whose genomic structure is similar to those of herpes simplex virus and varicella-zoster virus. Repeat regions of the MDV genome have been intensively investigated because of a potential relationship to MDV oncogenicity and abundant expression of immediate-early transcripts. In this study, a 1.6-kb immediate-early transcript was localized to the BamHI-I2 region by Northern (RNA) hybridization analysis. With cDNA cloning and sequencing, two cDNAs of 1.4 kb (C1) and 1.35 kb (C2) were identified. Both cDNAs are derived from spliced mRNAs spanning the BamHI-H and -I2 fragments. C1 and C2 use the same splice acceptors and 3' ends, but they differ at their 5' ends and utilize different splice donors. The upstream promoter-enhancer region of C1 cDNA has been defined as a bidirectional regulatory region shared by the MDV pp38 gene. Sequencing analysis shows two small open reading frames (ORFs) within each cDNA (ORF1a and ORF2 in C1, ORF1b and ORF2 in C2). Potential ORFs of the sequence have no significant homology with any known protein in the Swiss-Protein data base. DNA fragments encoding ORF1a and ORF1b were cloned into pGEX-3X vectors to produce glutathione S-transferase fusion proteins and induce antisera. In Western blot (immunoblot) analysis of MDV-infected-cell lysates, a 14-kDa polypeptide was identified by antisera against both ORF1a and ORF1b. This 14-kDa protein is expressed in cells which are lytically infected with MDV strains GA, Md11 passage 14 (oncogenic), and Md11 passage 83 (attenuated), as well as in the latently MDV-infected and transformed MSB-1 cell line.

Documentos Relacionados

• An Epstein-Barr virus immediate-early gene product trans-activates gene expression from the human immunodeficiency virus long terminal repeat.
• Identification of a unique Marek's disease virus gene which encodes a 38-kilodalton phosphoprotein and is expressed in both lytically infected cells and latently infected lymphoblastoid tumor cells.
• The Epstein-Barr virus BRLF1 immediate-early gene product transactivates the human immunodeficiency virus type 1 long terminal repeat by a mechanism which is enhancer independent.
• Nucleotide sequence of an immediate-early frog virus 3 gene.
• The Human Cytomegalovirus Major Immediate-Early Distal Enhancer Region Is Required for Efficient Viral Replication and Immediate-Early Gene Expression