BIG-3, a novel WD-40 repeat protein, is expressed in the developing growth plate and accelerates chondrocyte differentiation in vitro
BIG-3, a novel WD-40 repeat protein, is expressed in the developing growth plate and accelerates chondrocyte differentiation in vitro
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DOI：
10.1210/en.2003-1314
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发表时间：
2004-03-01
期刊：
影响因子：
4.8
通讯作者：
Demay, MB
中科院分区：
文献类型：
--
作者：
Gori, F;Demay, MB
在调节软骨细胞分化的连续步骤的局部信号传导途径中，骨形态发生蛋白（BMP）信号传导途径是其中之一。我们已经确定了一个新的基因，命名为BIG-3（BMP-2诱导的基因3 kb），在前成软骨细胞系MLB 13 MYC克隆17中以BMP调节的方式表达。BIG-3还在体内发育中的生长板中的增殖和肥大软骨细胞中表达。我们进行了研究，以解决是否BIG-3在软骨细胞分化中发挥功能性作用，使用小鼠克隆软骨ATDC 5细胞。BIG-3蛋白水平增加ITS（胰岛素，转铁蛋白，亚硒酸钠）诱导的ATDC 5分化和BMP-2治疗的反应。为了确定BIG-3的稳定表达是否可以改变软骨细胞分化的程序，用BIG-3的全长编码区（ATDC 5-BIG-3）或空载体（ATDC 5-EV）稳定转染ATDC 5细胞。在合并的ATDC 5-BIG-3克隆中观察到加速的基质蛋白聚糖合成。与ATDC 5-EV克隆相比，ATDC 5-BIG-3克隆中碱性磷酸酶和骨桥蛋白mRNA水平也增加。BIG-3的稳定表达在ITS存在和不存在的情况下也加速了矿化基质的形成。这些发现表明BIG-3在体外加速软骨细胞分化，结合观察到BIG-3在胚胎发育期间在生长板中表达，表明这种新蛋白可能在发育中的生长板中发挥体内调节作用。
Among the local signaling pathways that regulate the sequential steps of chondrocyte differentiation is the bone morphogenetic protein (BMP) signaling pathway. We have identified a novel gene, named BIG-3 (BMP-2-induced gene 3 kb) that is expressed in a BMP-regulated fashion in the prechondroblastic cell line MLB13MYC clone 17. BIG-3 is also expressed in proliferating and hypertrophic chondrocytes in the developing growth plate in vivo. We undertook studies to address whether BIG-3 played a functional role in chondrocyte differentiation, using mouse clonal chondrogenic ATDC5 cells. BIG-3 protein levels increased during ITS ( insulin, transferrin, sodium selenite)-induced ATDC5 differentiation and in response to BMP-2 treatment. To determine whether stable expression of BIG-3 could alter the program of chondrocytic differentiation, ATDC5 cells were stably transfected with the full-length coding region of BIG-3 (ATDC5-BIG-3) or with the empty vector (ATDC5-EV). Accelerated matrix proteoglycan synthesis was observed in the pooled ATDC5-BIG-3 clones. Alkaline phosphatase and osteopontin mRNA levels were also increased in ATDC5-BIG-3 clones compared with ATDC5-EV clones. Stable expression of BIG-3 also accelerated mineralized matrix formation in both the presence and absence of ITS. These findings, which demonstrate that BIG-3 accelerates chondrocyte differentiation in vitro, combined with the observation that BIG-3 is expressed in the growth plate during embryonic development, suggest that this novel protein is likely to play an in vivo regulatory role in the developing growth plate.