The p68 and p72 DEAD box RNA helicases interact with HDAC1 and repress transcription in a promoter-specific manner
1 Department of Molecular and Cellular Pathology, Ninewells Medical School, University of Dundee, DD1 9SY, UK
2 Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dow Street, DD1 5EH, UK
3 Molecular Oncology Group – McGill University Health Centre, 687 Pine Avenue West, Montreal, Quebec, H3A 1A1, Canada
4 Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, UK
5 Department of Microbiology and Immunology, McGill University, 3775 University Street, Montreal, H3A 2B4, Canada
BMC Molecular Biology 2004, 5:11 doi:10.1186/1471-2199-5-11Published: 6 August 2004
p68 (Ddx5) and p72 (Ddx17) are highly related members of the DEAD box family and are established RNA helicases. They have been implicated in growth regulation and have been shown to be involved in both pre-mRNA and pre-rRNA processing. More recently, however, these proteins have been reported to act as transcriptional co-activators for estrogen-receptor alpha (ERα). Furthermore these proteins were shown to interact with co-activators p300/CBP and the RNA polymerase II holoenzyme. Taken together these reports suggest a role for p68 and p72 in transcriptional activation.
In this report we show that p68 and p72 can, in some contexts, act as transcriptional repressors. Targeting of p68 or p72 to constitutive promoters leads to repression of transcription; this repression is promoter-specific. Moreover both p68 and p72 associate with histone deacetylase 1 (HDAC1), a well-established transcriptional repression protein.
It is therefore clear that p68 and p72 are important transcriptional regulators, functioning as co-activators and/or co-repressors depending on the context of the promoter and the transcriptional complex in which they exist.