|Kung H J|
Submitted to: Virus Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/1994
Publication Date: N/A
Citation: N/A Interpretive Summary: Marek's disease virus (MDV) causes tumors in chickens. The research goal was to identify ways to prevent tumor induction. One of the approaches we used was to find MDV genes related to the replication or reproduction of the virus. In this paper we identified a gene named DNA polymerase which is directly related to virus replication. This study helps our understanding on the process of Marek's disease growth and provides a chemical approach to inhibit virus replication.
Technical Abstract: DNA sequence analysis revealed that the gene coding for the Marek's Disease Virus (MDV) DNA polymerase is located within the BamHI-E fragment of the long unique region of the virus genome. Identification is based on an extensive amino acid homology between the MDV open reading frame and the DNA polymerase (UL30) of the herpes simplex virus. We describe here a 3,540-base-pair fragment of the MDV DNA as the viral DNA polymerase gene, along with the analysis of transcription and translation. Based on the sequences, a promoter, a poly A signal and a long open-reading frame can be identified. The calculated molecular size of this product is 1,180 amino acids with a Mr of 133,920 daltons. Northern blot hybridization showed a transcript of 4.0 kb. To analyze the gene product, we used bacterial tryE-fusion vector to express a portion of this gene and raised antisera against this fusion protein. This antisera specifically precipitated a protein of 135 Kd from lysates of MDV infected cells. MDV DNA polymerase showed extensive homology to five distantly related herpesviruses, equine herpesvirus (EHV), varicella-zoster virus (VZV), herpes simplex virus type 1 (HSV-1), Epstein-Barr virus (EBV), and human cytomegalovirus (HCMV). The comparison highlights nine highly conserved regions, three of which are at the N-terminal portion of the molecule. The remaining six region are located in the C-terminal portion of the molecule. The predicted structural characters are in good agreement with the published data on a number of human herpesvirus DNA polymerases. The identification of MDV DNA polymerase may lead to a better understanding of mechanisms of MDV replication.