RING1 is associated with the polycomb group protein complex and acts as a transcriptional repressor.
The Polycomb (Pc) protein is a component of a multimeric, chromatin-associated Polycomb group (PcG) protein complex, which is involved in stable repression of gene activity. The identities of components of the PcG protein complex are largely unknown. In a two-hybrid screen with a vertebrate Pc homolog as a target, we identify the human RING1 protein as interacting with Pc. RING1 is a protein that contains the RING finger motif, a specific zinc-binding domain, which is found in many regulatory proteins. So far, the function of the RING1 protein has remained enigmatic. Here, we show that RING1 coimmunoprecipitates with a human Pc homolog, the vertebrate PcG protein BMI1, and HPH1, a human homolog of the PcG protein Polyhomeotic (Ph). Also, RING1 colocalizes with these vertebrate PcG proteins in nuclear domains of SW480 human colorectal adenocarcinoma and Saos-2 human osteosarcoma cells. Finally, we show that RING1, like Pc, is able to repress gene activity when targeted to a reporter gene. Our findings indicate that RING1 is associated with the human PcG protein complex and that RING1, like PcG proteins, can act as a transcriptional repressor.
Satijn
D P
DP
E.C. Slater Institute, University of Amsterdam, The Netherlands.
Gunster
M J
MJ
van der Vlag
J
J
Hamer
K M
KM
Schul
W
W
Alkema
M J
MJ
Saurin
A J
AJ
Freemont
P S
PS
van Driel
R
R
Otte
A P
AP
D000595:Amino Acid Sequence; D002451:Cell Compartmentation; D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D029721:Drosophila Proteins; D006801:Humans; D007158:Immunologic Techniques; D019476:Insect Proteins / Q000378:metabolism*; D018386:Kinetochores / Q000648:ultrastructure; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D009698:Nucleoproteins / Q000378:metabolism; D063150:Polycomb Repressive Complex 1; D011233:Precipitin Tests; D011485:Protein Binding; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000502:physiology*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
C069077:BMI1 protein, human; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; D009687:Nuclear Proteins; D009698:Nucleoproteins; C066770:Pc protein, Drosophila; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins; C072820:ph-d protein, Drosophila; D063150:Polycomb Repressive Complex 1; C080355:RING1 protein, human