Viral interleukin 10 is critical for the induction of B cell growth transformation by Epstein-Barr virus.
We have used an efficient cDNA subtraction library procedure to identify newly induced genes in human B lymphocytes infected for 6 h with Epstein-Barr virus (EBV). Among the genes identified by automated sequencing of a random subset of clones from this library, one coded the EBV BCRF1 open reading frame, which specifies the viral interleukin 10 gene (vIL-10). This molecule is highly homologous to human (h)IL-10 and was previously thought to represent a "late" viral gene expressed only during the lytic phase of virus replication. Using gene amplification by reverse transcriptase polymerase chain reaction of B cell RNA obtained at varying times after infection, we detected vIL-10 expression within a few hours of EBV infection, followed, 20-30 h later by expression of hIL-10. Expression of both genes continued beyond the initial transformation phase (5-10 d) and was present in all transformed cell lines tested. When added at the time of viral infection, antisense (but not sense) oligonucleotides for vIL-10 mRNA (cytosolic half-life, approximately 6 h) prevented subsequent B cell transformation. The antisense effect was highly specific, leaving the expression levels of other transformation-related genes intact. Addition of exogenous (h)IL-10 rescued the transformation process in antisense-treated cells. Our observations establish vIL-10 as a new latency gene with a directly transformation-prerequisite function.
Miyazaki
I
I
Department of Pediatrics, University of Toronto, Hospital for Sick Children, Ontario, Canada.
Cheung
R K
RK
Dosch
H M
HM
D001402:B-Lymphocytes / Q000382:microbiology*; D001483:Base Sequence; D002472:Cell Transformation, Viral / Q000235:genetics / Q000502:physiology*; D002478:Cells, Cultured; D004247:DNA; D015870:Gene Expression; D005814:Genes, Viral; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000502:physiology*; D006801:Humans; D016753:Interleukin-10 / Q000502:physiology*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism
D012333:RNA, Messenger; D016753:Interleukin-10; D004247:DNA