title: Comparative transcriptional activity of five promoters in BAC-cloned MDV for the expression of the hemagglutinin gene of H9N2 avian influenza virus.
abstract: On the basis of recent studies, much attention has been given to recombinant MDV (rMDV)-based vaccines. During the construction of rMDV, the activity of promoters to transcribe foreign genes is one of the major factors that can affect protective efficacy. To investigate the transcription activity and efficacy of five different promoters, the advantage of an existing rMDV BAC infectious clone that had been previously constructed was used to construct rMDVs. The expression cassette of the hemagglutinin gene (HA) from a low pathogenic avian influenza virus (LPAIV) H9N2 strain was inserted into the US2 region under five selected promoters. These five promoters included three MDV endogenous promoters (the promoter for the gB gene and a bi-directional promoter in both directions for pp38 (ppp38) and 1.8 kb RNA transcripts (p1.8 kb)), and two exogenous promoters (CMV and SV40). Among these five promoters, the CMV promoter demonstrated the highest activity, followed by p1.8 kb and SV40, which had a similar transcriptional activity level. Two of the MDV endogenous promoters showed much lower transcriptional activities, particularly the promoter ppp38, which had the lowest activity. The results of the in vivo experiment proved that none of the three recombinant viruses of rGX-CMV-HA, rGX-SV40-HA and rGX-p1.8kb-HA provided protection in SPF chickens. Chickens vaccinated with rGX-pPP38-HA induced 50% and rGX-gB-HA induced 25% protection against the challenge with H9N2, respectively.
authors.affiliation: College of Veterinary Medicine, Shandong Agricultural University, Taian 271018, Shandong, China.
authors.forename: Chengtai
authors.initials: C
authors.lastname: Ma
authors.affiliation: School of Basic Medical Sciences, Taishan Medical College, Taian 271016, China.
authors.forename: Zhenjie
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: College of Veterinary Medicine, Shandong Agricultural University, Taian 271018, Shandong, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhao
authors.affiliation: College of Veterinary Medicine, Shandong Agricultural University, Taian 271018, Shandong, China.
authors.forename: Luntao
authors.initials: L
authors.lastname: Duan
authors.affiliation: College of Veterinary Medicine, Shandong Agricultural University, Taian 271018, Shandong, China.
authors.forename: Yaoyao
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: College of Veterinary Medicine, Shandong Agricultural University, Taian 271018, Shandong, China.
authors.forename: Fushou
authors.initials: F
authors.lastname: Zhang
authors.affiliation: College of Veterinary Medicine, Shandong Agricultural University, Taian 271018, Shandong, China.
authors.forename: Wenqing
authors.initials: W
authors.lastname: Chen
authors.affiliation: College of Veterinary Medicine, Shandong Agricultural University, Taian 271018, Shandong, China. Electronic address: zzcui@sdau.edu.cn.
authors.forename: Zhizhong
authors.initials: Z
authors.lastname: Cui
mesh_terms: D000818:Animals; D002645:Chickens; D022202:Chromosomes, Artificial, Bacterial; D003587:Cytomegalovirus / Q000235:genetics; D015870:Gene Expression; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000096:biosynthesis* / Q000235:genetics; D053127:Influenza A Virus, H9N2 Subtype / Q000235:genetics*; D025922:Mardivirus / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D013539:Simian virus 40 / Q000235:genetics; D014158:Transcription, Genetic
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus; D011994:Recombinant Proteins
keywords: H9N2; Promoters; Protective efficacy; Recombinant MDV; Transcriptional activity