TY - JOUR
T1 - Characterization of a bone-specific alkaline phosphatase in chick limb mesenchymal cell cultures
AU - Osdoby, Philip
AU - Caplan, Arnold I.
N1 - Funding Information:
This work was supported by grants from the National Institutes of Health, the March of Dimes, and the Arthritis Foundation. We are grateful for the expert technical assistance of Ms. Elizabeth Wilson and Ms. Katarina Ristich.
PY - 1981/8
Y1 - 1981/8
N2 - Previous morphometric and biochemical studies suggested that osteoblasts develop in cultures derived from phenotypically unexpressive stage 24 chick limb mesenchymal cells. Others have shown that osteoblast expression is marked by an increase in bone-specific alkaline phosphatase activity. Our results indicate that chick limb mesenchymal cells develop alkaline phosphatase activity that is identical to that of the chick embryonic bone-specific isoenzyme. The alkaline phosphatase isozymes were partially purified from samples of chick intestine, liver, stage 38 embryonic limbs, and cultures of stage 24 limb mesenchymal cells. These tissues were separately extracted with butanol, acetone precipitated, redissolved, and passed over a DEAE-Sephacel ion-exchange column and ion-filtration column (Sephadex A-25). From the data obtained during this purification scheme, we conclude that the alkaline phosphatase from stage 38 limbs (bones) and Day 4 cultures are identical, and this activity is different from the enzyme purified from intestine and liver. The cell culture isozyme has an apparent Km, heat lability, response to specific inhibitors, electrophoretic mobility, and molecular weight similar to those of bone-specific alkaline phosphatase. These observations support the view that osteoblastic progenitor cells are present in the stage 24 limb mesenchyme and that under specific culture conditions, bone development can be uniquely observed in vitro.
AB - Previous morphometric and biochemical studies suggested that osteoblasts develop in cultures derived from phenotypically unexpressive stage 24 chick limb mesenchymal cells. Others have shown that osteoblast expression is marked by an increase in bone-specific alkaline phosphatase activity. Our results indicate that chick limb mesenchymal cells develop alkaline phosphatase activity that is identical to that of the chick embryonic bone-specific isoenzyme. The alkaline phosphatase isozymes were partially purified from samples of chick intestine, liver, stage 38 embryonic limbs, and cultures of stage 24 limb mesenchymal cells. These tissues were separately extracted with butanol, acetone precipitated, redissolved, and passed over a DEAE-Sephacel ion-exchange column and ion-filtration column (Sephadex A-25). From the data obtained during this purification scheme, we conclude that the alkaline phosphatase from stage 38 limbs (bones) and Day 4 cultures are identical, and this activity is different from the enzyme purified from intestine and liver. The cell culture isozyme has an apparent Km, heat lability, response to specific inhibitors, electrophoretic mobility, and molecular weight similar to those of bone-specific alkaline phosphatase. These observations support the view that osteoblastic progenitor cells are present in the stage 24 limb mesenchyme and that under specific culture conditions, bone development can be uniquely observed in vitro.
UR - http://www.scopus.com/inward/record.url?scp=0019797077&partnerID=8YFLogxK
U2 - 10.1016/0012-1606(81)90324-9
DO - 10.1016/0012-1606(81)90324-9
M3 - Article
C2 - 6269926
AN - SCOPUS:0019797077
SN - 0012-1606
VL - 86
SP - 136
EP - 146
JO - Developmental Biology
JF - Developmental Biology
IS - 1
ER -