The CAAT-binding transcription factor 1/nuclear factor 1 binding site is important in beta-myosin heavy chain antisense promoter regulation in rats.
The CAAT-binding transcription factor 1/nuclear factor 1 binding site is important in beta-myosin heavy chain antisense promoter regulation in rats.
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DOI：
10.1113/expphysiol.2009.049692
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发表时间：
2009-12
影响因子：
2.7
通讯作者：
Haddad F
中科院分区：
文献类型：
--
作者：
Giger JM;Bodell PW;Baldwin KM;Haddad F
大鼠心脏表达两种肌球蛋白重链（MHC）亚型，β和α;这些基因串联排列在同一染色体上。我们已经报道了反义β RNA（AS β RNA）起始于β和α基因之间的基因间区（IG），并延伸至与β基因重叠。我们认为，在成年大鼠中，α正义和IG βAS RNA的表达都被IG双向启动子激活，βAS RNA的转录干扰了正义β，导致β mRNA水平低，α水平高，这是在典型大鼠心脏中观察到的表型。以前的报道检测了βAS启动子的活性，并显示βAS启动子的559 bp片段（−2285至−1726;相对于αMHC基因起始位点）在对照心脏中被激活，并在甲状腺功能减退时显著降低（丙硫氧嘧啶诱导）和糖尿病（链脲佐菌素诱导）的β AS RNA表达增加，甲状腺功能亢进大鼠（T3诱导）的β AS RNA表达增加，与内源性βAS RNA表达模式相似。在本文中，我们通过电泳迁移率变化分析证明心室核蛋白与核因子1/CAAT结合转录因子1（NF 1/CTF 1）结合位点相互作用，超迁移率分析表明该位点的蛋白质结合是抗遗传的。与CTF 1/NF 1因子相关。此外，在对照、STZ和PTU处理的大鼠中，559 bp启动子区域内的CTF 1/NF 1位点突变几乎消除了体内启动子活性。基于这些发现，我们得出结论，NF 1位点是βAS启动子调控的关键。
The rat heart expresses two myosin heavy chain (MHC) isoforms, β and α; these genes are arranged in tandem on the same chromosome. We have reported that an antisense (AS) β RNA starts in the intergenic (IG) region between β and α genes and extends to overlap the β gene. We propose that in adult rats, both the α sense and IG βAS RNA expression are activated by an IG bidirectional promoter and that the transcription of βAS RNA interferes with the sense β, resulting in low levels of β mRNA and high levels of α, a phenotype seen in a typical rat heart. A previous report examined the activity of the βAS promoter and showed that a 559 bp fragment of the βAS promoter (−2285 to −1726; relative to αMHC gene start site) injected into rat ventricle was activated in control heart, and decreased significantly in response to hypothyroidism (propylthiouracil induced) and diabetes (streptozotocin induced) and increased in hyperthyroid rats (T3 induced), similar in pattern to the endogenous βAS RNA. In the present paper, we demonstrate with electrophoretic mobility shift analyses that ventricular nuclear proteins are interacting with a nuclear factor 1/CAAT-binding transcription factor 1 (NF1/CTF1) binding site, and a supershift assay indicates that the protein binding at this site is antigenetically related to the CTF1/NF1 factor. Moreover, a mutation of the CTF1/NF1 site within the 559 bp promoter region nearly abolished promoter activity in vivo in control, STZ- and PTU-treated rats. Based on these findings, we conclude that the NF1 site is critical to βAS promoter regulation.