TY - JOUR
T1 - Tax-induced HTLV-I LTR transcriptional activation is modulated by phosphorylation
AU - Saggioro, D.
AU - Forino, M.
AU - Penzo, A.
AU - Pesce, M.
AU - Oliviero, S.
AU - Chieco-Bianchi, L.
PY - 1994
Y1 - 1994
N2 - We studied the effect of protein phosphatase and kinase inhibitors on Tax-mediated transcription of constructs carrying the receptor gene chloramphenicol acetyl transferase under the control of either the full-length LTR of HTLV-I or three copies of the tax-responsive 21-bp repeats. We observed that treatment with okadaic acid, which inhibits the serine/threonine protein phosphatases type 1 and 2A, reduced HTLV-I LTR, transcriptional activation in MT2 and K562 cells; on the contrary, the enhancer activity of the 21-bp sequences was significantly increased in both cell lines; treatment with the protein kinase C inhibitor H-7 blocked Tax-mediated transcription of both constructs. We also found that treatment with sodium orthovanadate, a tyrosine phosphatase inhibitor, reduced Tax-mediated activation of both plasmids. These findings indicated that specific serine/threonine phosphorylation events are required for Tax-mediated HTLV-1 LTR activation and also suggested that phosphorylation at tyrosine residues is involved in this process.
AB - We studied the effect of protein phosphatase and kinase inhibitors on Tax-mediated transcription of constructs carrying the receptor gene chloramphenicol acetyl transferase under the control of either the full-length LTR of HTLV-I or three copies of the tax-responsive 21-bp repeats. We observed that treatment with okadaic acid, which inhibits the serine/threonine protein phosphatases type 1 and 2A, reduced HTLV-I LTR, transcriptional activation in MT2 and K562 cells; on the contrary, the enhancer activity of the 21-bp sequences was significantly increased in both cell lines; treatment with the protein kinase C inhibitor H-7 blocked Tax-mediated transcription of both constructs. We also found that treatment with sodium orthovanadate, a tyrosine phosphatase inhibitor, reduced Tax-mediated activation of both plasmids. These findings indicated that specific serine/threonine phosphorylation events are required for Tax-mediated HTLV-1 LTR activation and also suggested that phosphorylation at tyrosine residues is involved in this process.
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U2 - 10.1006/bbrc.1994.2717
DO - 10.1006/bbrc.1994.2717
M3 - Article
C2 - 7999095
AN - SCOPUS:0028088606
VL - 205
SP - 666
EP - 673
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 1
ER -