Transcription factor PHOX2A regulates the human α3 nicotinic receptor subunit gene promoter
Transcription factor PHOX2A regulates the human α3 nicotinic receptor subunit gene promoter
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DOI：
10.1074/jbc.m608616200
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发表时间：
2007-05-04
影响因子：
4.8
通讯作者：
Fornasari, Diego
中科院分区：
文献类型：
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作者：
Benfante, Roberta;Flora, Adriano;Fornasari, Diego
PHOX2A 是一种配对样同源域转录因子，参与指定自主神经系统。它还参与去甲肾上腺素能神经递质表型的转录控制，因为它调节酪氨酸羟化酶和多巴胺-β-羟化酶的基因表达。这项研究的结果表明，PHOX2A 的人类直系同源物还能够调节人类 α3 烟碱乙酰胆碱受体基因的转录，该基因编码神经节型烟碱受体的配体结合亚基。特别是，我们通过染色质免疫沉淀和 DNA Pulldown 测定证明 PHOX2A 在 α 3 启动子的 SacI-NcoI 区域组装，并通过共转染实验证明它通过 60 bp 最小启动子发挥其转录作用。 PHOX2A似乎并不直接与DNA结合，并且其DNA结合域对于α3基因转录的调节似乎是部分可有可无的。然而，正如我们的免疫共沉淀试验的结果所表明的，它可能与 Sp1 建立直接或间接的蛋白质-蛋白质相互作用，从而通过不依赖于 DNA 的机制调节 α3 的表达。由于α3亚基在每个终末分化的神经节细胞中表达，这是其表达受PHOX2蛋白调节的“泛自主”基因的第一个例子。
PHOX2A is a paired-like homeodomain transcription factor that participates in specifying the autonomic nervous system. It is also involved in the transcriptional control of the noradrenergic neurotransmitter phenotype as it regulates the gene expression of tyrosine hydroxylase and dopamine-beta-hydroxylase. The results of this study show that the human orthologue of PHOX2A is also capable of regulating the transcription of the human alpha 3 nicotinic acetylcholine receptor gene, which encodes the ligand-binding subunit of the ganglionic type nicotinic receptor. In particular, we demonstrated by chromatin immunoprecipitation and DNA pulldown assays that PHOX2A assembles on the SacI-NcoI region of alpha 3 promoter and, by co-transfection experiments, that it exerts its transcriptional effects by acting through the 60-bp minimal promoter. PHOX2A does not seem to bind to DNA directly, and its DNA binding domain seems to be partially dispensable for the regulation of alpha 3 gene transcription. However, as suggested by the findings of our co-immunoprecipitation assays, it may establish direct or indirect protein-protein interactions with Sp1, thus regulating the expression of alpha 3 through a DNA-independent mechanism. As the alpha 3 subunit is expressed in every terminally differentiated ganglionic cell, this is the first example of a " pan-autonomic" gene whose expression is regulated by PHOX2 proteins.