TY - JOUR
T1 - Age-resolving osteopetrosis
T2 - A rat model implicating microphthalmia and the related transcription factor TFE3
AU - Weilbaecher, Katherine N.
AU - Hershey, Christine L.
AU - Takemoto, Clifford M.
AU - Horstmann, Martin A.
AU - Hemesath, Timothy J.
AU - Tashjian, Armen H.
AU - Fisher, David E.
PY - 1998/3/2
Y1 - 1998/3/2
N2 - Microphthalmia (Mi) is a basic helix-loop-helix-leucine tipper (b-HLH- ZIP) transcription factor implicated in pigmentation, mast cells, and bone development. Two dominant-negative mi alleles (mi/mi and Mi(or)/Mi(or)) 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.
AB - Microphthalmia (Mi) is a basic helix-loop-helix-leucine tipper (b-HLH- ZIP) transcription factor implicated in pigmentation, mast cells, and bone development. Two dominant-negative mi alleles (mi/mi and Mi(or)/Mi(or)) 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.
UR - http://www.scopus.com/inward/record.url?scp=0032473407&partnerID=8YFLogxK
U2 - 10.1084/jem.187.5.775
DO - 10.1084/jem.187.5.775
M3 - Article
C2 - 9480987
AN - SCOPUS:0032473407
SN - 0022-1007
VL - 187
SP - 775
EP - 785
JO - Journal of Experimental Medicine
JF - Journal of Experimental Medicine
IS - 5
ER -