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Age-resolving osteopetrosis: a rat model implicating microphthalmia and the related transcription factor TFE3.
- Source :
-
The Journal of experimental medicine [J Exp Med] 1998 Mar 02; Vol. 187 (5), pp. 775-85. - Publication Year :
- 1998
-
Abstract
- Microphthalmia (Mi) is a basic helix-loop-helix-leucine zipper (b-HLH-ZIP) transcription factor implicated in pigmentation, mast cells, and bone development. Two dominant-negative mi alleles (mi/mi and Mior/Mior) in mice cause osteopetrosis. In contrast, osteopetrosis has not been observed in a number of recessive mi alleles, suggesting the existence of Mi protein partners important in osteoclast function. An osteopetrotic rat of unknown genetic defect (mib) has been described whose skeletal sclerosis improves dramatically with age and that is associated with pigmentation defects reminiscent of mouse mi alleles. Here we report that this rat strain harbors a large genomic deletion encompassing the 3' half of mi including most of the b-HLH-ZIP region. Osteoclasts from these animals lack Mi protein in contrast to wild-type rat, mouse, and human osteoclasts. Mi is not detectable in primary osteoblasts. In addition TFE3, a b-HLH-ZIP transcription factor related to Mi, was found to be expressed in osteoclasts, but not osteoblasts, and to coimmunoprecipitate with Mi. These results demonstrate the existence of members of a family of biochemically related transcription factors that may cooperate to play a central role in osteoclast function and possibly in age-related osteoclast homeostasis.
- Subjects :
- Animals
Base Sequence
Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
Gene Expression
Helix-Loop-Helix Motifs
Humans
Leucine Zippers
Mice
Microphthalmia-Associated Transcription Factor
Molecular Sequence Data
Osteoblasts metabolism
RNA, Messenger genetics
Rats
Rats, Mutant Strains
Sequence Alignment
Sequence Homology, Nucleic Acid
DNA-Binding Proteins genetics
DNA-Binding Proteins physiology
Microphthalmos genetics
Osteoclasts physiology
Osteopetrosis etiology
Transcription Factors physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0022-1007
- Volume :
- 187
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- The Journal of experimental medicine
- Publication Type :
- Academic Journal
- Accession number :
- 9480987
- Full Text :
- https://doi.org/10.1084/jem.187.5.775