Correlation of the steady-state RNA levels among the alpha-subunit of prolyl 4-hydroxylase and the alpha 1 and alpha 2 chains of type I collagen during growth of chicken embryo tendon fibroblasts.
The relative steady-state levels of RNAs encoding type I collagen and prolyl 4-hydroxylase were examined in exponentially growing primary cultures of chicken embryo tendon fibroblasts. The RNA levels of the alpha 1 and alpha 2 chains of type I collagen were maximal when the fibroblasts reached the confluent state. The RNA levels of the alpha-subunit of prolyl 4-hydroxylase were also maximal at confluency and rose and fell with the RNA levels of the two collagen chains. The RNA levels of the beta-subunit of prolyl 4-hydroxylase did not correlate with the changes observed for the alpha-subunit or for either chain of type I collagen. The RNA levels of the beta-subunit were slightly higher than the RNA levels of the alpha-subunit. These results support our hypothesis that the synthesis of the alpha-subunit and thus the association of newly synthesized alpha-subunits with pre-existing beta-subunits is the rate-limiting factor in determining prolyl 4-hydroxylase activity in cultured cells.
Bassuk
J A
JA
Department of Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway 08854.
Berg
R A
RA
D000818:Animals; D015152:Blotting, Northern; D002478:Cells, Cultured; D002642:Chick Embryo; D003094:Collagen / Q000737:chemistry / Q000235:genetics*; D005347:Fibroblasts / Q000378:metabolism; D007700:Kinetics; D011393:Procollagen-Proline Dioxygenase / Q000737:chemistry / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism*; D013710:Tendons / Q000196:embryology / Q000378:metabolism
D012333:RNA, Messenger; D003094:Collagen; D011393:Procollagen-Proline Dioxygenase