Upholt W B, Vertel B M, Dorfman A
Proc Natl Acad Sci U S A. 1979 Oct;76(10):4847-51. doi: 10.1073/pnas.76.10.4847.
Total RNA, prepared from chicken limb bud cultures undergoing differentiation to cartilage, has been translated in a wheat germ cell-free protein-synthesizing system. Antibodies against chondroitin sulfate proteoglycan core protein immunoprecipitate a single component which migrates as a protein of 340,000 daltons in sodium dodecyl sulfate/polyacrylamide gels. The messenger RNA for this protein sediments at approximately 27 S in 70% formamide or aqueous sucrose gradients. The 340,000-dalton protein is present in cell-free translation products directed by RNA prepared from limb bud cultures and sternae and is absent in cell-free translation directed by RNA prepared from embryonic calvaria or liver. The level of synthesis of this protein is greatly reduced when RNA prepared from limb bud cultures inhibited from differentiation by BrdUrd is used. (Pre)pro alpha 1(I), -alpha 2(I), and -alpha 1(II) collagen bands have been identified on gels by electrophoresis of collagenase-digested or immunoprecipitated cell-free translation products directed by RNA from differentiating limb bud cultures, embryonic sternae, and embryonic calvaria.
从正在分化为软骨的鸡肢体芽培养物中制备的总RNA，已在麦胚无细胞蛋白质合成系统中进行翻译。抗硫酸软骨素蛋白聚糖核心蛋白的抗体免疫沉淀出一种单一成分，该成分在十二烷基硫酸钠/聚丙烯酰胺凝胶中作为一种340,000道尔顿的蛋白质迁移。该蛋白质的信使RNA在70%甲酰胺或水性蔗糖梯度中沉降约27S。340,000道尔顿的蛋白质存在于由肢体芽培养物和胸骨制备的RNA指导的无细胞翻译产物中，而不存在于由胚胎颅骨或肝脏制备的RNA指导的无细胞翻译中。当使用由被BrdUrd抑制分化的肢体芽培养物制备的RNA时，该蛋白质的合成水平大大降低。通过对来自分化肢体芽培养物、胚胎胸骨和胚胎颅骨的RNA指导的胶原酶消化或免疫沉淀的无细胞翻译产物进行电泳，已在凝胶上鉴定出（前）原α1（I）、-α2（I）和-α1（II）胶原条带。
