Identification of osteopontin in isolated rabbit osteoclasts.
Bone remodeling is a complex process coupling bone formation and resorption. Osteoblasts, the bone-forming cells, are known to produce various bone matrix proteins and cytokines; however, little is known about protein factors produced by osteoclasts or bone-resorbing cells. A method utilizing the high affinity of osteoclasts for tissue culture dishes was developed to isolate a large number of pure osteoclasts from rabbit long bones. A cDNA library was then constructed from these isolated osteoclasts, and differential cDNA screening was performed between osteoclasts and spleen cells. Two clones representing osteoclast-specific clones, named OC-1 and OC-2, were isolated. By Northern blot analysis, OC-1 was expressed in osteoclasts and in kidneys, whereas OC-2 was specific for osteoclasts. OC-1 was found to encode osteopontin from its nucleotide sequence, and therefore, osteopontin may have other functions for osteoclastic bone resorption besides osteoclast attachment to bone.
Tezuka
K
K
Department of Oral Anatomy, Meikai University School of Dentistry, Sakado, Japan.
Sato
T
T
Kamioka
H
H
Nijweide
P J
PJ
Tanaka
K
K
Matsuo
T
T
Ohta
M
M
Kurihara
N
N
Hakeda
Y
Y
Kumegawa
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001842:Bone and Bones / Q000502:physiology; D002478:Cells, Cultured; D004247:DNA / Q000235:genetics; D015342:DNA Probes; D015723:Gene Library; D006801:Humans; D008969:Molecular Sequence Data; D010010:Osteoclasts / Q000166:cytology / Q000502:physiology*; D053495:Osteopontin; D011061:Poly A / Q000235:genetics / Q000302:isolation & purification; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger; D011817:Rabbits; D012689:Sequence Homology, Nucleic Acid; D012795:Sialoglycoproteins / Q000032:analysis / Q000235:genetics*
D015342:DNA Probes; D012333:RNA, Messenger; C506895:SPP1 protein, human; D012795:Sialoglycoproteins; D053495:Osteopontin; D011061:Poly A; D012313:RNA; D004247:DNA