Multiple transcripts encoded by the thyroid-specific enhancer-binding protein (T/EBP) thyroid-specific transcription factor-1 (TTF-1) gene: Evidence of autoregulation
Multiple transcripts encoded by the thyroid-specific enhancer-binding protein (T/EBP) thyroid-specific transcription factor-1 (TTF-1) gene: Evidence of autoregulation
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DOI：
10.1210/en.139.4.1999
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发表时间：
1998-04-01
期刊：
影响因子：
4.8
通讯作者：
Kimura, S
中科院分区：
文献类型：
--
作者：
Oguchi, H;Kimura, S
通过对大鼠甲状腺特异性增强子结合蛋白（T/EBP）/甲状腺特异性转录因子-1（TTIF-1）基因的互补DNA克隆、测序和北方印迹分析，鉴定了该基因的多个转录本。鉴定了6种不同类型的互补DNA，它们在5'非编码区不同; 4种含有不同长度的内含子，而另外2种没有内含子。核糖核酸酶保护分析表明，多个启动子分散在整个上游区域，这些不同的启动子与选择性剪接一起使用导致一个家庭的T/EBP信使RNA（mRNA）物种。在肺癌细胞系中表达的人T/EBP基因中也发现了类似的表达模式。较长的T/EBP mRNA在缺乏TSH（-TSH）的大鼠FRTL-5甲状腺细胞中比在存在TSH（+TSH）的细胞中更丰富。转染分析使用大鼠T/EBP基因的ATG起始密码子的上游连接到荧光素酶报告质粒的DNA显示了类似的相对活性曲线之间的-TSH和+TSH培养条件，这表明，较长的mRNA在-TSH条件下的丰度可能不直接相关的启动子活性的差异。相反，TSH状态可能在维持细胞的生理状态方面发挥作用。大鼠和人的T/EBP基因的上游DNA共享一个集群的高和低的序列相似性，并分别拥有24和18个推定的T/EBP结合位点。共转染分析的T/EBP启动子-报告结构与T/EBP表达载体到人HepG 2细胞，不表达T/EBP，表明自动调节可能参与控制大鼠和人T/EBP基因的表达。
Multiple transcripts derived from the gene encoding rat thyroid-specific enhancer-binding protein (T/EBP)/thyroid-specific transcription factor-1 (TTIF-1) were identified by complementary DNA cloning and sequencing, and Northern blotting analyses. Six different types of complementary DNAs were identified that differ at their 5' non-coding regions; four contain an intron of different lengths, whereas the other two possess no intron. Ribonuclease protection analyses revealed that multiple promoters are scattered throughout the upstream region, and the usage of these different promoters together with alternative splicing leads to a family of T/EBP messenger RNA (mRNA) species. A similar pattern of expression was also found in the human T/EBP gene expressed in a lung carcinoma cell line. Longer T/EBP mRNAs are more abundant in rat FRTL-5 thyroid cells maintained in the absence of TSH (-TSH) than in cells maintained in the presence of TSH (+TSH). Transfection analyses using the rat T/EBP gene DNA upstream of the ATG initiation codon connected to the luciferase reporter plasmid showed a similar relative activity profile between -TSH and +TSH culture conditions, suggesting that the abundance of longer mRNAs in -TSH conditions may not directly correlate with differences in promoter activities. Rather, TSH status might have a role in maintaining the physiological state of the cells. The upstream DNA of the rat and human T/EBP genes share a cluster of high and low sequence similarities, and both possess respectively 24 and 18 putative T/EBP-binding sites throughout. Cotransfection analyses of the T/EBP promoter-reporter constructs with a T/EBP expression vector into human HepG2 cells, which do not express T/EBP, suggested that autoregulation may be involved in controlling both rat and human T/EBP gene expression.