Robust circadian rhythmicity of Drosophila melanogaster requires the presence of lateral neurons:: a brain-behavioral study of disconnected mutants
Robust circadian rhythmicity of Drosophila melanogaster requires the presence of lateral neurons:: a brain-behavioral study of disconnected mutants
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DOI：
10.1007/s003590050192
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发表时间：
1998-04-01
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通讯作者：
Helfrich-Förster, C
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作者：
Helfrich-Förster, C
黑腹果蝇断开（迪斯科）位点的突变破坏了视觉系统中的神经细胞模式，导致许多视叶神经元丧失。果蝇的假定昼夜节律起搏神经元（背侧和腹侧外侧神经元）通常位于缺失的细胞中，并且大多数迪斯科果蝇的行为都存在心律失常。在这项研究中，我发现腹侧外侧神经元 (LN(v)s) 偶尔存在，并在迪斯科突变体中激发强大的昼夜节律。在 357 只迪斯科蝇个体中，发现了 4 只具有强大昼夜节律的动物。所有四个都保留了 LN(v) 以及上原大脑中的终端。在大约 20% 的果蝇中发现了残余或双昼夜节律；其余的果蝇完全失去了心律失常。一只具有残余节律的果蝇和两只心律失常的果蝇也有一些 LN(v) 染色。然而，这些果蝇上原大脑中缺乏 LNv 纤维。结果表明，如果 LNv 末端到达上原大脑，则单个 LN(v) 的存在足以激发运动活动的稳健昼夜节律。 20% 没有 LN(v) 的果蝇中存在残余或双昼夜节律，表明其他细胞也有助于运动活动的节律控制。
Mutations at the disconnected (disco) locus of Drosophila melanogaster disrupt neural cell patterning in the visual system, leading to the loss of many optic lobe neurons. Drosophila's presumptive circadian pacemaker neurons - the dorsal and ventral lateral neurons - are usually among the missing cells, and most disco flies are behaviorally arrhythmic. In this study, I show that ventral lateral neurons (LN(v)s) are occasionally present and provoke robust circadian rhythmicity in disco mutants. Of 357 individual disco flies four animals with robust circadian rhythmicity were found. All four retained LN(v)s together with terminals in the superior protocerebrum. Residual or bi-circadian rhythmicity was found in about 20% of all flies; the remaining flies were completely arrhythmic. One of the flies with residual rhythmicity and two of the arrhythmic flies also had some LN(v)s stained. However, these flies lacked the LNv fibers in the superior protocerebrum. The results suggest that the presence of single LN(v)s is sufficient to provoke robust circadian rhythmicity in locomotor activity if the LNv terminals reach the superior protocerebrum. The presence of residual or bi-circadian rhythmicity in 20% of the flies without LN(v)s indicates that also other cells contribute to the rhythmic control of locomotor activity.