Human T-cell leukemia virus type 2 Rex protein increases stability and promotes nuclear to cytoplasmic transport of gag/pol and env RNAs.
The human T-cell leukemia virus (HTLV) Rex protein is essential for efficient expression of the viral structural and enzymatic gene products. In this study, we assessed the role of the HTLV-2 rex gene in viral RNA expression and Gag protein production. Following transfection of human JM4 T cells with wild-type and rex mutant full-length proviral constructs, PCR was used for semiquantitative analysis of specific viral RNA transcripts. In the presence of Rex, the total amount of steady-state viral RNA was increased fourfold. Rex significantly up-regulated the level of incompletely spliced RNAs by increasing RNA stability and was associated with a twofold down-regulation of the completely spliced tax/rex RNA. PCR analysis of subcellular RNA fractions, isolated from transfected cells, indicated that the level of gag/pol and env cytoplasmic RNAs were increased 7- to 9-fold in the presence of Rex, whereas Gag protein production was increased 130-fold. These data indicate that HTLV-2 Rex increases the stability and promotes nucleus-to-cytoplasm transport of the incompletely spliced viral RNAs, ultimately resulting in increased structural protein production. Moreover, this model system provides a sensitive approach to further characterize HTLV gene expression from full-length proviral clones following transfection of human T cells.
Kusuhara
K
K
Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2363, USA.
Anderson
M
M
Pettiford
S M
SM
Green
P L
PL
D001402:B-Lymphocytes / Q000821:virology; D001692:Biological Transport; D002460:Cell Line; D002467:Cell Nucleus / Q000821:virology; D003593:Cytoplasm / Q000821:virology; D015683:Gene Products, gag / Q000502:physiology*; D015684:Gene Products, pol / Q000502:physiology*; D016370:Gene Products, rex / Q000502:physiology*; D015367:Human T-lymphotropic virus 2 / Q000502:physiology*; D006801:Humans; D012367:RNA, Viral / Q000502:physiology*; D013601:T-Lymphocytes / Q000821:virology; D014759:Viral Envelope Proteins / Q000502:physiology*; D014779:Virus Replication
D015683:Gene Products, gag; D015684:Gene Products, pol; D016370:Gene Products, rex; D012367:RNA, Viral; D014759:Viral Envelope Proteins