Sexually Dimorphic Shaping of Interneuron Dendrites Involves the Hunchback Transcription Factor
Sexually Dimorphic Shaping of Interneuron Dendrites Involves the Hunchback Transcription Factor
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DOI：
10.1523/jneurosci.4861-10.2011
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发表时间：
2011-04-06
影响因子：
5.3
通讯作者：
Yamamoto, Daisuke
中科院分区：
文献类型：
--
作者：
Goto, Junpei;Mikawa, Yoshitaka;Yamamoto, Daisuke
在单个神经元水平上，果蝇大脑的性别二型性在解剖学上已经得到了很好的表征，但关于细胞性别差异产生的分子机制，除了神经性决定基因Fru起关键作用外，人们还知之甚少。表达FU的Mal中间神经元团在三个方面具有性别二型性：组成该簇的细胞数量女性为5个，男性为30个；同侧神经突起在女性中不存在，在男性中存在；对侧神经突起在女性的食道下神经节中形成Y形分支，而在男性的末端为简单的马尾状结构。通过在复眼中筛选由fru(+)过度表达引起的粗糙度修饰物，我们确定了驼背(HB)的一个功能丧失等位基因是这一表型的抑制基因。在幼虫期和成虫期，Hb在大多数Fru型表达神经元中表达。在男性大脑中敲除Mal MARCM克隆中的Hb可导致对侧神经突起分支模式的部分去血管化，但不影响细胞数量和同侧神经突起的形成。本研究结果提示，Hb对于男性典型的对侧神经突起的形成是必要的。
Sexual dimorphism of the brain has been well characterized anatomically in Drosophila melanogaster at the single neuron level, yet little is known about the molecular mechanism whereby cellular sex differences are generated except that the neural sex determination gene fruitless (fru) plays a key role. The fru-expressing mAL interneuron cluster is sexually dimorphic in three aspects: the number of cells composing the cluster is 5 in females and 30 in males; the ipsilateral neurite is absent in females and present in males; the contralateral neurite forms Y-shaped branches in the subesophageal ganglion in females while it ends with a simple horsetail-like structure in males. By screens in the compound eye for modifiers of roughness induced by fru(+) overexpression, we identified a loss-of-function allele of hunchback (hb) to be a suppressor of this phenotype. Hb was expressed in most of the fru-expressing neurons in the pupal and adult stages. Knocking down hb in mAL MARCM (Mosaic Analysis with a Repressible Cell Marker) clones in the male brain resulted in partial demasculinization of the branching pattern of the contralateral neurites without affecting the cell number and the ipsilateral neurite formation. The present results suggest that Hb is essential for male-typical shaping of the contralateral neurites by Fru.