The p68 and p72 DEAD box RNA helicases interact with HDAC1 and repress transcription in a promoter-specific manner.
BACKGROUND
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 (ER alpha). 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.


RESULTS
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.


CONCLUSIONS
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.
Wilson
Brian J
BJ
Department of Molecular and Cellular Pathology, Ninewells Medical School, University of Dundee, DD1 9SY, UK. brian.wilson@molonc.mcgill.ca
Bates
Gaynor J
GJ
Nicol
Samantha M
SM
Gregory
David J
DJ
Perkins
Neil D
ND
Fuller-Pace
Frances V
FV
D000230:Adenocarcinoma / Q000473:pathology; D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D000256:Adenoviridae / Q000235:genetics; D001859:Bone Neoplasms / Q000473:pathology; D001943:Breast Neoplasms / Q000473:pathology; D002460:Cell Line; D045744:Cell Line, Tumor; D002850:Chromatography, Gel; D053487:DEAD-box RNA Helicases; D004742:Enhancer Elements, Genetic / Q000235:genetics; D017930:Genes, Reporter; D006561:Herpes Simplex / Q000235:genetics; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases / Q000502:physiology*; D006801:Humans; D007668:Kidney; D012516:Osteosarcoma / Q000473:pathology; D010446:Peptide Fragments / Q000737:chemistry / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000235:genetics*; D025941:Protein Interaction Mapping; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D017434:Protein Structure, Tertiary; D020365:RNA Helicases / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000502:physiology; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D017384:Sequence Deletion; D013539:Simian virus 40 / Q000235:genetics; D013937:Thymidine Kinase / Q000235:genetics; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic; D014162:Transfection
D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D015534:Trans-Activators; D011494:Protein Kinases; D013937:Thymidine Kinase; C110550:HDAC1 protein, human; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases; D000251:Adenosine Triphosphatases; C102004:DDX17 protein, human; C506749:Ddx5 protein, human; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases