Friend murine leukemia virus A8 regulates Env protein expression through an intron sequence.
Friend murine leukemia virus (Fr-MLV) produces unspliced mRNAs, as well as singly-spliced mRNAs by which the Env protein is generated. We investigated the role of the intron within the Fr-MLV gene in Env expression using vectors with serially truncated introns. The up-regulatory regions, the 361-878 and the 5135-5399 fragments, and the down-regulatory regions, the 1904-2849 and the 3995-4287 fragments, were found to influence the splicing efficiency. The Env protein expression level was proportional to the amount of env-mRNA. Furthermore, we found that the splicing process is important to acquire env-mRNA stability, and it also promotes translation of the Env protein. These splicing-dependent phenomena were not observed when luciferase expression vectors were analyzed. These findings indicated that the Env protein expression level in MLV is regulated at multiple steps: the env-mRNA expression level is determined by the splicing efficiency, and the stability of env-mRNA is acquired through the splicing process.
Yamamoto
Naoki
N
Department of Bioinformatics, Soka University, Tokyo, Japan.
Takase-Yoden
Sayaka
S
D000818:Animals; D001483:Base Sequence; D018929:Cell Culture Techniques; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D005622:Friend murine leukemia virus / Q000235:genetics* / Q000378:metabolism*; D015967:Gene Expression Regulation, Viral; D015686:Gene Products, env / Q000235:genetics / Q000378:metabolism*; D007438:Introns / Q000235:genetics; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D041681:NIH 3T3 Cells; D012326:RNA Splicing; D020871:RNA Stability / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism
D015686:Gene Products, env; D012333:RNA, Messenger; D012367:RNA, Viral; D008156:Luciferases