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Recruitment of human cyclin T1 to nuclear bodies through direct interaction with the PML protein
Author(s) -
Marcello Alessandro,
Ferrari Aldo,
Pellegrini Vittorio,
Pegoraro Gianluca,
Lusic Marina,
Beltram Fabio,
Giacca Mauro
Publication year - 2003
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdg205
Subject(s) - biology , transactivation , promyelocytic leukemia protein , cyclin a2 , microbiology and biotechnology , cyclin d , cyclin a , p tefb , nuclear export signal , cyclin , transcription factor , cyclin dependent kinase , nuclear protein , cell nucleus , kinase , genetics , cyclin dependent kinase 2 , protein kinase a , cytoplasm , promoter , gene , cell cycle , gene expression
Human cyclin T1, the cyclin partner of Cdk9 kinase in the positive transcription elongation factor b (P‐TEFb), is an essential cellular cofactor that is recruited by the human immunodeficiency virus type 1 (HIV‐1) Tat transactivator to promote transcriptional elongation from the HIV‐1 long terminal repeat (LTR). Here we exploit fluorescence resonance energy transfer (FRET) to demonstrate that cyclin T1 physically interacts in vivo with the promyelocytic leukaemia (PML) protein within specific subnuclear compartments that are coincident with PML nuclear bodies. Deletion mutants at the C‐terminal region of cyclin T1 are negative for FRET with PML and fail to localize to nuclear bodies. Cyclin T1 and PML are also found associated outside of nuclear bodies, and both proteins are present at the chromatinized HIV‐1 LTR promoter upon Tat transactivation. Taken together these results suggest that PML proteins regulate Tat‐ mediated transcriptional activation by modulating the availability of cyclin T1 and other essential cofactors to the transcription machinery.