title: The microphthalmia transcription factor (MITF) contains two N-terminal domains required for transactivation of osteoclast target promoters and rescue of mi mutant osteoclasts.
abstract: The microphthalmia transcription factor (MITF) regulates gene expression during differentiation of several distinct cell types, including osteoclasts. A structure/function analysis was performed to determine whether transcription activation domains were important for MITF action in osteoclasts. In addition to a previously characterized acidic activation necessary for melanocyte differentiation, the analysis defined a second potential activation domain located between amino acids 140 and 185. This second domain is required for MITF transactivation of two probable targets, the E-cadherin promoter and the tartrate-resistant acid phosphatase promoter, in transient transfection assays. An intact MITF gene rescued differentiation when introduced into osteoclasts derived from mi/mi mice using a retrovirus vector. In parallel experiments, an MITF gene lacking the acidic-activation domain rescued differentiation twofold less efficiently than wild type, and a gene lacking the region between amino acid residues 140 and 185 rescued differentiation tenfold less efficiently than wild type. The results indicate that the N-terminal region of MITF is necessary for activation of gene expression in osteoclasts and provides one mechanism by which this factor regulates distinct target genes in different cell types.
authors.affiliation: Department of Molecular Genetics and the Comprehensive Cancer Center, Ohio State University, Columbus 43210, USA.
authors.forename: Kim C
authors.initials: KC
authors.lastname: Mansky
authors.forename: Kavita
authors.initials: K
authors.lastname: Marfatia
authors.forename: Georgia H
authors.initials: GH
authors.lastname: Purdom
authors.forename: Alex
authors.initials: A
authors.lastname: Luchin
authors.forename: David A
authors.initials: DA
authors.lastname: Hume
authors.forename: Michael C
authors.initials: MC
authors.lastname: Ostrowski
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000235:genetics*; D051379:Mice; D051739:Microphthalmia-Associated Transcription Factor; D009154:Mutation; D010010:Osteoclasts / Q000166:cytology / Q000502:physiology*; D010449:Peptide Mapping; D011401:Promoter Regions, Genetic / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics; D015533:Transcriptional Activation
chemical_list: D004268:DNA-Binding Proteins; D051739:Microphthalmia-Associated Transcription Factor; C497235:Mitf protein, mouse; D014157:Transcription Factors