科研之友
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摘要
Expression of the collagen genes in the ligament has not been fully described. In this study, we isolated a cDNA encoding the alpha 2 type I [alpha 2(I)] collagen of the rabbit and, by utilizing reverse transcriptase polymerase chain reaction (RT-PCR) technique, quantified the levels of the collagen gene expression in the knee ligaments of the rabbit during the newborn period and in adult age. A cDNA done, RCOL1A2, having a largest insert of 1,617 bp was isolated from a cDNA library in lambda gt10 constructed from rabbit fetus calvarie. The clone encodes the C-terminal 526 amino acid residues of the alpha 2(I) collagen, that exhibit 92% and 90% homologies to the corresponding portions of the human and mouse collagens, respectively. Quantitation of the mRNA in the ligaments by RT-PCR was performed by establishing optimal conditions so that an exponential phase of amplification as to the amount of template RNA was obtained. Results of RT-PCR assay revealed that the rabbits newborn at 15 to 30 days after birth showed a highest level of the collagen mRNA relative to those of the beta-actin in the anterior cruciate ligament, which then rapidly decreased within the following 20 to 30 days and reached to a steady state low level as the animal develops. On the other hand, the levels of the alpha 2(I) collagen mRNA in the anterior cruciate ligament and posterior cruciate ligament were significantly lower than in the patella tendon, medial collateral ligament and lateral collateral ligament of the rabbits at 150 days after birth. These findings strongly imply that the synthesis of type I collagen in the rabbit knee ligaments is regulated essentially at the level of gene transcription, which is active in the newborn period but becomes to be repressed, as the animal matures.
- 出版日期1995-8
