p160 Myb-binding protein interacts with Prep1 and inhibits its transcriptional activity.
Prep1 is known to interact in vivo with Pbx1 to regulate development and organogenesis. We have identified a novel Prep1-interacting protein, p160 c-Myb binding protein (p160). p160 and Pbx1 compete for Prep1 in vitro, and p160 inhibits Prep1-dependent HoxB2 expression in retinoic acid-treated NT2-D1 cells. The N-terminal physiologically truncated form of p160, p67, binds the sequence 63LFPLL67 in the HR1 domain of Prep1. Mutation of both L63 and L66 impairs the binding of Prep1 to both p160/p67 and Pbx1. The sequences required to bind Prep1 are mainly located in residues 51 to 151. Immunofluorescence colocalization and coimmunoprecipitation of endogenous p160 and Prep1 are induced by ActD, which translocates p160 from the nucleolus to the nucleoplasm. These data therefore show that p160 is a novel regulator of Prep1-Pbx1 transcriptional activity.
Díaz
Víctor M
VM
Molecular Genetics Unit, Department of Molecular Biology and Functional Genomics, Università Vita Salute San Raffaele and DIBIT, H San Raffaele, via Olgettina 58, 20132 Milan, Italy.
Mori
Silvia
S
Longobardi
Elena
E
Menendez
Guillermo
G
Ferrai
Carmelo
C
Keough
Rebecca A
RA
Bachi
Angela
A
Blasi
Francesco
F
D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins; D005786:Gene Expression Regulation; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D000075062:Pre-B-Cell Leukemia Transcription Factor 1; D016601:RNA-Binding Proteins; D016415:Sequence Alignment; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; C110421:Mybbp1a protein, mouse; D009687:Nuclear Proteins; C481797:Pbx1 protein, mouse; C491412:Pknox1 protein, mouse; D000075062:Pre-B-Cell Leukemia Transcription Factor 1; D016601:RNA-Binding Proteins; D014157:Transcription Factors