Premium
The La‐related protein LARP7 is a component of the 7SK ribonucleoprotein and affects transcription of cellular and viral polymerase II genes
Author(s) -
Markert Andreas,
Grimm Michael,
Martinez Javier,
Wiesner Julia,
Meyerhans Andreas,
Meyuhas Oded,
Sickmann Albert,
Fischer Utz
Publication year - 2008
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.1038/embor.2008.72
Subject(s) - rna polymerase ii , rna polymerase ii holoenzyme , transcription factor ii d , p tefb , biology , general transcription factor , transcription (linguistics) , microbiology and biotechnology , transcription factor ii f , ribonucleoprotein , transcription factor ii b , rna polymerase , rna , promoter , biochemistry , gene , gene expression , linguistics , philosophy
The positive transcription elongation factor b (P‐TEFb) is a heterodimeric complex composed of cyclin‐dependent kinase 9 and its regulator cyclin T1/2. It stimulates transcription elongation by phosphorylation of serine 2 residues in the carboxy‐terminal domain of polymerase II. 7SK RNA and HEXIM proteins can antagonize transcriptional stimulation by sequestering P‐TEFb in a catalytically inactive ribonucleoprotein (RNP). Here, we show that the previously uncharacterized La‐related protein 7 (LARP7) has a role in 7SK‐mediated regulation of transcription. LARP7 binds to the highly conserved 3′‐terminal U‐rich stretch of 7SK RNA and is an integral part of the 7SK RNP. On stimulation, LARP7 remains associated with 7SK RNA, whereas P‐TEFb is released. Interestingly, reduction of LARP7 by RNA interference enhances transcription from cellular polymerase II promoters, as well as a TAT‐dependent HIV‐1 promoter. Thus, LARP7 is a negative transcriptional regulator of polymerase II genes, acting by means of the 7SK RNP system.