title: Dlxin-1, a novel protein that binds Dlx5 and regulates its transcriptional function.
abstract: Dlx5, a member of the Dlx family of homeodomain proteins, plays a critical role in bone development and fracture healing. To understand the molecular mechanism underlying the transcriptional regulation by Dlx5, we performed yeast two-hybrid screening and isolated a novel protein, Dlxin-1, that binds Dlx5 and regulates its transcriptional function. Dlxin-1 cDNA encodes a 775-amino acid protein that has a partial homology with necdin at the C terminus and 25 repeats of hexapeptides (WQXPXX) in the middle region. Dlxin-1 mRNA is expressed in various adult tissues, but not the spleen, and also in osteoblastic and chondrogenic cell lines. During embryogenesis, a strong signal for Dlxin-1 mRNA was found in cell layers surrounding cartilaginous elements in bone rudiment during digit formation. Dlxin-1 binds not only Dlx5 but also Dlx7 and Msx2 and forms homomultimers in vivo. Transfection and reporter gene assays indicate that Dlxin-1 activates the transcriptional function of Dlx5. Therefore, Dlxin-1 may act as a regulator of the function of Dlx family members in bone formation.
authors.affiliation: Department of Geriatric Research, National Institute for Longevity Sciences, 36-3 Gengo, Morioka-cho, Obu, Aichi 474-8522, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Masuda
authors.forename: A
authors.initials: A
authors.lastname: Sasaki
authors.forename: H
authors.initials: H
authors.lastname: Shibuya
authors.forename: N
authors.initials: N
authors.lastname: Ueno
authors.forename: K
authors.initials: K
authors.lastname: Ikeda
authors.forename: K
authors.initials: K
authors.lastname: Watanabe
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000951:Antigens, Neoplasm; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D002460:Cell Line; D003001:Cloning, Molecular; D018398:Homeodomain Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D015534:Trans-Activators / Q000737:chemistry / Q000378:metabolism / Q000502:physiology; D014157:Transcription Factors; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
chemical_list: D000951:Antigens, Neoplasm; D002352:Carrier Proteins; C100596:DLX5 protein, human; C501120:Dlx5 protein, mouse; D018398:Homeodomain Proteins; C120897:MAGED1 protein, human; C486541:Maged1 protein, mouse; C486542:Maged1 protein, rat; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D015534:Trans-Activators; D014157:Transcription Factors