Amino Acid Polymorphisms in the Basic Region of Meq of Vaccine Strain CVI988 Drastically Diminish the Virulence of Marek's Disease Virus.

ABSTRACT: Marek's disease virus (MDV) is the etiological agent of Marek's disease (MD), a lymphoproliferative disorder in chickens. Polymorphisms in the MDV-encoded oncoprotein Meq are shared among field strains and correlate with their virulence. The attenuated vaccine strain CVI988 harbors unique amino acid polymorphisms in Meq, particularly at positions 71, 77, and 326. In this study, we investigated the impact of these polymorphisms on Meq protein function and MDV virulence. Reporter assays revealed that the substitutions, particularly A71S and K77E, markedly impaired the transcriptional regulatory activity of Meq. To evaluate their effect on virulence, we generated a recombinant MDV based on the very virulent RB-1B strain, encoding Meq with A71S and K77E substitutions (rRB-1B_Meq71/77). Chicken

SUBMITTER: Sato J 

PROVIDER: S-EPMC12298729 | biostudies-literature | 2025 Jun

REPOSITORIES: biostudies-literature