Molecular cloning and sequence analysis of Meq gene of Marek's disease virus.

摘要

Marek's disease (MD) is an economically important neoplastic disease of chickens caused by Marek's disease virus (MDV) in the poultry industry. To understand the molecular characteristics of MDV Meq gene, we studied 15 amino acid sequences of Meq gene. The full-length cDNAs of Meq contained a complete coding sequence (CDS), 1020bp, and they encoded 339 amino acid residues. The result showed that the C-terminal region of Meq gene contained a proline-rich sequence, including several repeats with proline residue, and 18 variable amino acid sites were variable in Meq amino acid sequences, accounting for 5.3% of all amino acids. The mutations at position 115(V->A), 139(T->A) and 176(A->R) occurred in MDVs from China, and amino acid residues at position 77(K) and 80(D) were unique in most very virulent MDVs and very virulent plus MDVs. Moreover, AH-MDV sequence cloned from Anhui had high homology to other Meq sequences isolated in China. Evolution analysis further revealed that AH-MDV and domestic Meq sequences had a close genetic relationship.