Department of Biochemistry, School of Medicine, Dongguk University, and Medical Institute of Dongguk University, Gyeongju, 780-714, Republic of Korea.
Gene. 2013 Apr 15;518(2):368-75. doi: 10.1016/j.gene.2012.12.102. Epub 2013 Jan 19.
Osterix (Osx) is a transcription factor required for osteoblast differentiation during intramembranous and endochondral ossification. Recently, several reports have described novel functions of Osx in chondrocyte differentiation. In an in vitro study, in which the effects of Osx gene silencing were examined in mouse chondrogenic ATDC5 cells, chondrocyte marker genes were found to be expressionally downregulated and chondrocyte differentiation reduced. On the other hand, in vivo studies based on chondrocyte-specific Osx knockouts demonstrated impaired endochondral bone formation with delayed chondrocyte differentiation and reduced cartilage matrix ossification. However, little is known about the mechanism or targets of Osx involved in the control of chondrocyte differentiation. Here, we attempted to high-density of Affymetrix GeneChip microarray to investigate global gene expression profile changes caused by Osx knockdown in ATDC5 chondrocytes. The mRNA expressions of 112 genes were significantly modified by Osx knockdown: 68 genes were upregulated and 44 genes downregulated. Functional categories of gene expression classified by gene ontology demonstrated that genes related to cell adhesion, development, and signal transduction were highly affected by Osx knockdown. The expressions of differential genes, such as Sfrp2, Sema3a, Nox4, Rgs4, Zfp521, Has2, Sox6, Scn2a1, Sirpa, and Thbs2, were validated by quantitative real-time PCR. This study shows that expression profiling can be used to identify genes that are transcriptionally modified following Osx knockdown and to reveal the molecular mechanism of chondrocyte differentiation regulated by Osx.
osterix(osx)是一种转录因子，在膜内成骨和软骨内成骨过程中，对成骨细胞的分化是必需的。最近，有几项报道描述了 osx 在软骨细胞分化中的新功能。在一项体外研究中，研究人员在鼠软骨细胞株 atdc5 中敲低 osx 基因，发现软骨细胞标志物的表达下调，软骨细胞分化减少。另一方面，基于软骨细胞特异性 osx 敲除的体内研究表明，软骨内骨形成受损，软骨细胞分化延迟，软骨基质矿化减少。然而，osx 调控软骨细胞分化的机制或靶点知之甚少。在这里，我们试图通过高密度 affymetrix genechip 微阵列来研究 osx 敲低对 atdc5 软骨细胞中全基因组表达谱变化的影响。osx 敲低后，有 112 个基因的表达发生了显著改变：68 个基因上调，44 个基因下调。通过基因本体论对基因表达的功能分类表明，与细胞黏附、发育和信号转导相关的基因受 osx 敲低的影响最大。差异基因如 sfrp2、sema3a、nox4、rgs4、zfp521、has2、sox6、scn2a1、sirpa 和 thbs2 的表达通过实时定量 pcr 进行验证。本研究表明，表达谱分析可用于鉴定 osx 敲低后转录修饰的基因，并揭示 osx 调控软骨细胞分化的分子机制。
