Grover J, Roughley P J
Genetics Unit, Shriners Hospital for Crippled Children, Montreal, Quebec, Canada.
Biochem J. 1993 Apr 15;291 ( Pt 2)(Pt 2):361-7. doi: 10.1042/bj2910361.
The chondrocytes in human articular cartilage from subjects of all ages express mRNAs for both of the aggregating proteoglycans aggrecan and versican, although the level of expression of versican mRNA is much lower than that of aggrecan mRNA. Aggrecan shows alternative splicing of the epidermal growth factor (EGF)-like domain within its C-terminal globular region, but there is no evidence for a major difference in situ in the relative expression of this domain with age. At all ages studied from birth to the mature adult, a greater proportion of transcripts lacked the EGF domain. The relative proportions of the two transcripts did not change upon culture and passage of isolated chondrocytes. In contrast, the neighbouring complement regulatory protein (CRP)-like domain was predominantly expressed irrespective of age, but cell culture did result in variation of the splicing of this domain. Versican possesses two EGF-like domains and one CRP-like domain, but at all ages the three domains were predominantly present in all transcripts. This situation persisted upon culture and passage of the chondrocytes. Thus, unlike aggrecan, the versican expressed by human articular cartilage does not appear to undergo alternative splicing of its C-terminal globular region, either in cartilage in situ or in chondrocytes in culture.
在各个年龄段受试者的人类关节软骨中，软骨细胞均表达聚集蛋白聚糖聚集蛋白聚糖和多功能蛋白聚糖的mRNA，尽管多功能蛋白聚糖mRNA的表达水平远低于聚集蛋白聚糖mRNA。聚集蛋白聚糖在其C末端球状区域内显示出表皮生长因子（EGF）样结构域的可变剪接，但没有证据表明该结构域的相对表达在原位会随年龄产生重大差异。从出生到成年的所有研究年龄段中，更大比例的转录本缺乏EGF结构域。分离的软骨细胞在培养和传代后，这两种转录本的相对比例没有变化。相比之下，相邻的补体调节蛋白（CRP）样结构域无论年龄大小均主要表达，但细胞培养确实导致该结构域剪接的变化。多功能蛋白聚糖具有两个EGF样结构域和一个CRP样结构域，但在所有年龄段，这三个结构域均主要存在于所有转录本中。软骨细胞在培养和传代后，这种情况依然存在。因此，与聚集蛋白聚糖不同，人类关节软骨表达的多功能蛋白聚糖在原位软骨或培养的软骨细胞中，其C末端球状区域似乎都不会发生可变剪接。
