rHox: A homeobox gene expressed in osteoblastic cells
rHox: A homeobox gene expressed in osteoblastic cells
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DOI：
10.1002/jcb.240590409
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发表时间：
1995-12-01
影响因子：
4
通讯作者：
Morrison, NA
中科院分区：
文献类型：
--
作者：
Hu, YS;Flanagan, J;Morrison, NA
同源结构域蛋白的特征在于具有螺旋-转角-螺旋基序的保守结构域。这些蛋白质在组织分化和增殖中充当调节因子。然而，它们在成骨细胞分化调节中的作用尚不清楚。在这项研究中，我们已经确定和特点的同源异型盒基因在成骨细胞样细胞。这个基因，称为rHox，是从大鼠成骨细胞样细胞的cDNA文库中分离出来的。该cDNA全长1,375 bp，含有329 bp的非编码前导序列、735 bp的开放阅读框和312 bp的3'端非编码序列。序列比较表明，rHox与小鼠Pmx基因（也称为MHox）在氨基酸水平上完全相同，在核苷酸水平上有90%的同源性。Southwestern印迹和凝胶位移分析均表明，rHox具有结合胶原1 α 1和骨钙素启动子的潜力。使用rHox表达载体的转染实验显示出对靶启动子活性的强烈抑制，无论靶启动子是否含有同源结构域结合反应元件。这些数据表明，rHox是一种有效的基因表达负调控因子，尽管rHox在骨基因调控中的具体作用仍有待确定。(C)1995年Wiley-Liss，Inc.
Homeodomain proteins are characterized by a conserved domain with a helix-turn-helix motif. These proteins act as regulatory factors in tissue differentiation and proliferation. However, their role in the regulation of osteoblast differentiation is unknown. In this study we have identified and characterized a homeobox gene in osteoblast-like cells. This gene, termed rHox, was isolated from a cDNA library derived from rat osteoblast-like cells. The nucleotide sequence of the 1,375 base pair (bp) cDNA contains a noncoding leader sequence of 329 bp, a 735 bp open reading frame, and 312 bp of 3' noncoding sequence. Sequence comparison demonstrates that rHox is identical to the mouse Pmx gene (also called MHox) at the amino acid level and 90% homologous at the nucleotide level. Both Southwestern blotting and gel shift analyses indicate that rHox has potential to bind both the collagen 1 alpha 1 and the osteocalcin promoters. Transfection experiments using an rHox expression vector showed a strong repression of target promoter activity, regardless of whether the target promoters contained homeodomain binding response elements. These data suggest that rHox is a potent negative regulator of gene expression, although the specific role of rHox in bone gene regulation remains to be determined. (C) 1995 Wiley-Liss, Inc.