Sande S, Privalsky M L
Section of Microbiology, University of California at Davis 95616, USA.
Mol Endocrinol. 1996 Jul;10(7):813-25. doi: 10.1210/mend.10.7.8813722.
Nuclear hormone receptors are the largest known family of eukaryotic transcription factors and serve as critical effectors of vertebrate homeostasis, growth, and differentiation. The precise transcriptional response mediated by a given nuclear hormone receptor is dictated by hormone, promoter, and cellular context, and many nuclear hormone receptors function bimodally as both transcriptional activators and repressors. We report here the identification of a family of proteins, denoted TRACs (T3 receptor-associating cofactors), which physically interact with nuclear hormone receptors and can modulate the transcriptional properties of these receptors. TRACs associate with retinoic acid, retinoid X, and thyroid hormone receptors, as well as the PML-RAR alpha and v-Erb A oncoproteins. Certain TRAC forms attenuate target gene expression and may serve as corepressors, whereas other TRAC family members appear to counteract these effects. We suggest that TRACs and related cofactors may participate in dictating the pleiotropic transcriptional capacities of the nuclear hormone receptors.
核激素受体是已知最大的真核转录因子家族，是脊椎动物体内平衡、生长和分化的关键效应因子。特定核激素受体介导的精确转录反应由激素、启动子和细胞环境决定，许多核激素受体具有双重功能，既是转录激活因子又是转录抑制因子。我们在此报告鉴定出一类蛋白质，称为TRACs（T3受体相关辅因子），它们与核激素受体发生物理相互作用，并能调节这些受体的转录特性。TRACs与视黄酸、视黄醇X和甲状腺激素受体以及PML-RARα和v-Erb A癌蛋白相关联。某些TRAC形式可减弱靶基因表达，可能作为共抑制因子，而其他TRAC家族成员似乎可抵消这些作用。我们认为TRACs和相关辅因子可能参与决定核激素受体的多效转录能力。
