Shoji W, Yamamoto T, Obinata M
Department of Cell Biology, Tohoku University, Sendai, Japan.
J Biol Chem. 1994 Feb 18;269(7):5078-84.
Id is considered to be a negative regulator of basic helix-loop-helix proteins, which play important roles in cell type-specific transcription and cell lineage commitment. The Id gene was first cloned in murine erythroleukemia (MEL) cells, which can be induced to differentiate toward erythrocytes with Me2SO, and its mRNA decreases after differentiation in various types of cells. In this report, we demonstrate that overexpression of Id interferes with MEL cell differentiation and that inhibition of differentiation is accompanied by reduction in expression of three erythroid-specific genes. While down-regulation of Id is an early event in the differentiation process of MEL cells, E-box binding activity of these cells increases only at a later stage of differentiation, and this late increase is reduced by the overexpression of Id in the early stage. Sequential changes in the activity of several basic helix-loop-helix proteins thus appeared to be involved in erythroid differentiation.
Id被认为是碱性螺旋-环-螺旋蛋白的负调节因子，这些蛋白在细胞类型特异性转录和细胞谱系定向中发挥重要作用。Id基因最初是在小鼠红白血病（MEL）细胞中克隆出来的，该细胞可被二甲亚砜诱导向红细胞分化，并且其mRNA在各种类型细胞分化后会减少。在本报告中，我们证明Id的过表达会干扰MEL细胞分化，并且分化抑制伴随着三个红系特异性基因表达的降低。虽然Id的下调是MEL细胞分化过程中的早期事件，但这些细胞的E盒结合活性仅在分化后期增加，并且早期Id的过表达会降低这种后期增加。因此，几种碱性螺旋-环-螺旋蛋白活性的顺序变化似乎参与了红系分化。
