Gene expression in the mouse growth plate

纵向骨生长是一个复杂的过程，开始软骨细胞增殖和随后的肥大和分泌细胞外基质。随后基质矿化、血管侵入、软骨细胞凋亡和骨细胞取代软骨细胞导致骨形成。生长板的软骨细胞被分为四个解剖区，反映了它们的细胞特征和组织结构。在静息区（RZ），细胞外基质与细胞体积的比例相当高。软骨细胞呈现扁平的外观，开始分裂，并组织成从增殖区（PZ）延伸到成熟区（MZ）的柱状物。肥大区（HZ）内的细胞分裂并长大，各带内的软骨细胞在生化和形态上存在明显差异。为了更好地表征控制骨生长的遗传程序，在从生长板的四个先前定义的区域显微解剖的软骨细胞中分析基因表达。这项研究是第一次以这种分辨率检查生长板，并通过测量约34，000个推定转录本的表达进一步扩展了以前的工作。我们发现生长板中不同区域的基因表达存在显著差异，这可能有助于调节生长板中软骨细胞的成熟。

Longitudinal bone growth is a complex process that begins chondrocyte proliferation and subsequent hypertrophy and secretion of extracellular matrix. Subsequently matrix mineralization, vascular invasion, chondrocyte apoptosis, and replacement of chondrocytes by osteocytes lead to the formation of bone. The chondrocytes of the growth plate have been classified into four anatomic zones, reflecting their cellular features and the tissue architecture. In the resting zone (RZ),the ratio of extracellular matrix to cell volume is quite high. The chondrocytes take on a flattened appearance, begin to divide, and organize into columns that extend from proliferating zone (PZ) to maturing zone (MZ). The dividing cells separate from each other and grow larger in the hypertrophic zone (HZ).There are notable biochemical and morphological differences among chondrocytes in each zone. In order to better characterize the genetic program controlling bone growth, gene expression was analyzed in chondrocytes microdissected from four previously defined zones of the growth plate. This study is the first to examine the growth plate at such resolution and further extends previous work by measuring expression of ~34,000 putative transcripts. We identified significant differences in gene expression among zones in growth plate, which likely contribute to the regulation of chondrocyte maturation in the growth plate.