Ben-Shahar Y, Leung H-T, Pak W L, Sokolowski M B, Robinson G E
Department of Entomology, University of Illinois at Urbana-Champaign, 320 Morrill Hall, 505 S. Goodwin Avenue, Urbana, IL 61801, USA.
J Exp Biol. 2003 Jul;206(Pt 14):2507-15. doi: 10.1242/jeb.00442.
Division of labor in honey bee colonies is influenced by the foraging gene (Amfor), which encodes a cGMP-dependent protein kinase (PKG). Amfor upregulation in the bee brain is associated with the age-related transition from working in the hive to foraging for food outside, and cGMP treatment (which increases PKG activity) causes precocious foraging. We present two lines of evidence in support of the hypothesis that Amfor affects division of labor by modulating phototaxis. We first show that a subset of worker bees involved in the removal of corpses from the hive had forager-like brain levels of Amfor brain expression despite being middle aged; age-matched food-handlers, who do not leave the hive to perform their job, had low levels of Amfor expression. This finding suggests that occupations that involve working outside the hive are associated with high levels of Amfor in brain. Secondly, foragers were much more positively phototactic than hive bees in a laboratory assay, and cGMP treatment caused a precocious onset of positive phototaxis. The cGMP effect was not due to a general increase in behavioral activity; cGMP treatment had no effect on locomotor activity under either constant darkness or a light:dark regime. The cGMP effect also was not due to changes in circadian rhythmicity; cGMP treatment had no effect on age at onset of locomotor circadian rhythmicity or the period of rhythmicity. The effects of Amfor on phototaxis are not related to peripheral processing; electroretinogram analysis revealed no effect of cGMP treatment on photoreceptor activity and no differences between untreated hive bees and foragers. The cAMP/PKA pathway does not appear to be playing a similar role to cGMP/PKG in the honey bee; cAMP treatment did not affect phototaxis and gene expression analysis revealed task-related differences only for the gene encoding the regulatory subunit, but not the catalytic subunit, of PKA. Our findings implicate one neural process associated with honey bee division of labor that can be affected by naturally occurring changes in the expression of AMFOR:
蜜蜂蜂群中的分工受觅食基因（Amfor）影响，该基因编码一种环鸟苷酸依赖性蛋白激酶（PKG）。蜜蜂大脑中Amfor的上调与从蜂巢内工作到外出觅食的年龄相关转变有关，而环鸟苷酸处理（可增加PKG活性）会导致早熟觅食。我们提供了两条证据来支持Amfor通过调节趋光性影响分工这一假说。我们首先表明，尽管处于中年，但参与从蜂巢中清除尸体的一部分工蜂大脑中Amfor的表达水平与觅食者相似；年龄匹配的负责处理食物、不离开蜂巢工作的工蜂，其Amfor表达水平较低。这一发现表明，涉及蜂巢外工作的职业与大脑中高水平的Amfor有关。其次，在实验室试验中，觅食者比蜂巢蜜蜂的趋光性更强，而环鸟苷酸处理导致趋光性早熟出现。环鸟苷酸的作用并非由于行为活动的普遍增加；环鸟苷酸处理在持续黑暗或明暗交替条件下对运动活动均无影响。环鸟苷酸的作用也不是由于昼夜节律的变化；环鸟苷酸处理对运动昼夜节律开始的年龄或节律周期均无影响。Amfor对趋光性的影响与外周处理无关；视网膜电图分析显示，环鸟苷酸处理对光感受器活性没有影响，未处理的蜂巢蜜蜂和觅食者之间也没有差异。在蜜蜂中，环腺苷酸/蛋白激酶A途径似乎没有起到与环鸟苷酸/蛋白激酶G类似的作用；环腺苷酸处理不影响趋光性，基因表达分析显示，仅编码蛋白激酶A调节亚基而非催化亚基的基因存在与任务相关的差异。我们的研究结果表明，一种与蜜蜂分工相关的神经过程可能会受到AMFOR表达的自然变化影响：
