Pagliuca A, Bartoli P C, Saccone S, Della Valle G, Lania L
Dipartimento di Genetica, Biologia Generale e Molecolare, Università Federico II, Via Mezzocannone 8, Naples, Italy.
Genomics. 1995 May 1;27(1):200-3. doi: 10.1006/geno.1995.1026.
Transcription factors containing a basic helix-loop-helix (bHLH) motif regulate the expression of tissue-specific genes in a number of mammalian and insect systems. DNA-binding activity of the bHLH proteins is dependent upon formation of homo- and/or heterodimers. Dominant negative HLH proteins (Id-related genes) also contain the HLH-dimerization domain but lack the DNA-binding basic domain. Consequently, Id proteins inhibit binding to DNA and transcriptional transactivation by heterodimerization with bHLH proteins. We report here the cDNA sequence of a novel human HLH gene (HGMW-approved symbol ID4) that lacks the basic domain. ID4 is differentially expressed in adult organs in four mRNA molecules, which are presumably a result of differential splicing and/or alternative usage of the polyadenylation sites. Transfection experiments indicated that enforced expression of Id-4H protein inhibits the trans-activation of the muscle creatine kinase E-box enhancer by MyoD. Finally, we localized the ID4 gene to the chromosome 6p21-p22 region.
含有碱性螺旋-环-螺旋（bHLH）基序的转录因子在许多哺乳动物和昆虫系统中调节组织特异性基因的表达。bHLH蛋白的DNA结合活性取决于同二聚体和/或异二聚体的形成。显性负性HLH蛋白（Id相关基因）也含有HLH二聚化结构域，但缺乏DNA结合碱性结构域。因此，Id蛋白通过与bHLH蛋白异二聚化来抑制与DNA的结合和转录反式激活。我们在此报告一个缺乏碱性结构域的新型人类HLH基因（HGMW批准符号ID4）的cDNA序列。ID4在成体器官中以四种mRNA分子差异表达，这可能是差异剪接和/或聚腺苷酸化位点的交替使用的结果。转染实验表明，Id-4H蛋白的强制表达抑制了MyoD对肌肉肌酸激酶E盒增强子的反式激活。最后，我们将ID4基因定位到6号染色体p21-p22区域。
