Sequence analysis of meq oncogene among Polish strains of Marek's disease.

The main goal of the present study was to analyse the nucleotide and amino acid sequence of Meq--the main oncoprotein of Marek's disease virus. The conducted analysis of the nucleotide sequences of MDV has shown a significant similarity between Polish and reference strains of MDV assigned to the vvMDV and vv+MDV pathotypes. Some of the detected nucleotide point mutations were specific only for Polish strains. The sequence analysis has shown a number of single substitutions and two poly-amino acid insertions among strains defined as mild-pathogenic (mMDV) and one attenuated vaccine strain CVI988--Rispens. These results indicate that there is a close relation between changes in nucleotide or amino acid sequence of meq and the virulence of Polish MDV strains.