Positive and negative regulation of odor receptor gene choice in Drosophila by acj6.
Positive and negative regulation of odor receptor gene choice in Drosophila by acj6.
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DOI：
10.1523/jneurosci.3525-09.2009
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发表时间：
2009-10-14
期刊：
影响因子：
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通讯作者：
Carlson JR
中科院分区：
文献类型：
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作者：
Bai L;Goldman AL;Carlson JR
个体嗅觉受体神经元（orn）如何从众多气味受体基因中选择表达哪些基因，目前还知之甚少。Acj6 （Abnormal chemosensory jump 6，异常化学感觉跳跃6）是果蝇上颌触须（果蝇的两种成年嗅觉器官之一）中调控ORN身份和Or（气味受体）基因表达所必需的ppo结构域转录因子。然而，Acj6在这一过程中的作用机制尚未被研究。在这里，我们系统地研究了Acj6在上颌触须和触角orn的主要亚群中的作用。我们通过反复的体外选择过程确定了Acj6的结合位点。该位点位于Acj6调控的Or基因的上游，Acj6与Or启动子中的该位点结合。突变分析表明，该位点对体内的Or调控至关重要。令人惊讶的是，在acj6成虫中发现了一种新的ORN类，它是由一种幼虫Or基因的异位表达引起的，该基因在野生型中通过acj6结合位点被抑制。因此，Acj6直接参与受体基因的选择过程；它在这个过程的逻辑中起着积极和消极的双重作用，并在划分幼虫和成虫的受体库中起作用。
Little is known about how individual olfactory receptor neurons (ORNs) select, from among many odor receptor genes, which genes to express. Acj6 (Abnormal chemosensory jump 6) is a POU-domain transcription factor essential for the specification of ORN identity and Or (odor receptor) gene expression in the Drosophila maxillary palp, one of the two adult olfactory organs. However, the mechanism by which Acj6 functions in this process has not been investigated. Here we systematically examine the role of Acj6 in the maxillary palp and in a major subset of antennal ORNs. We define an Acj6 binding site by a reiterative in vitro selection process. The site is found upstream of Or genes regulated by Acj6, and Acj6 binds to the site in Or promoters. Mutational analysis shows that the site is essential for Or regulation in vivo. Surprisingly, a novel ORN class in acj6 adults is found to arise from ectopic expression of a larval Or gene, which is repressed in wild-type via an Acj6 binding site. Thus Acj6 acts directly in the process of receptor gene choice; it plays a dual role, positive and negative, in the logic of the process, and acts in partitioning the larval and adult receptor repertoires.