Rex of human T‐cell leukemia virus type I (HTLV‐I) and Rev of human immunodeficiency virus 1 (HIV‐1) are post‐transcriptional regulators of viral gene expression. By means of affinity chromatography, we purified an 18‐kDa cellular protein that bound to the conserved leucine‐motif/activation domain of HTLV‐I Rex or HIV‐1 Rev. The protein that was purified through a Rev‐affinity column was found to bind to Rex immunoprecipitated with anti‐Rex IgG from an HTLV‐I‐producing cell line. We analyzed the purified ≈ 18‐kDa protein biochemically and identified it as prothymosin α. The binding activity of prothymosin α to Rev or Rex was completely abolished when the ɛ‐amino groups of its lysine residues were chemically modified by N‐succinimidyl‐3‐(4‐hydroxy‐3,5‐diodo‐phenyl)propionate. The functional relationship between the nuclear protein prothymosin α and Rex‐Rev is discussed.
- Rex of human T‐cell leukemia virus type I (HTLV‐I)
- human immunodeficiency virus type 1 (HIV‐1)
- interaction with Rev and Rex
- prothymosin α
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