Sialyltransferase regulates nervous system function in Drosophila.
Sialyltransferase regulates nervous system function in Drosophila.
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DOI：
10.1523/jneurosci.5253-09.2010
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发表时间：
2010-05-05
期刊：
影响因子：
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通讯作者：
Panin VM
中科院分区：
文献类型：
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作者：
Repnikova E;Koles K;Nakamura M;Pitts J;Li H;Ambavane A;Zoran MJ;Panin VM
在脊椎动物中，唾液酸化聚糖参与广泛的生物学过程，影响神经系统的发育和功能。虽然糖基化的复杂性和唾液酸转移酶之间的功能冗余为揭示哺乳动物中唾液酸化的生物学作用提供了障碍，但果蝇具有唯一的脊椎动物型唾液酸转移酶DSiaT，与其哺乳动物对应物具有显著的同源性，这表明果蝇可能是研究唾液酸化功能的合适模型。为了探索这种可能性，并研究唾液酸化在果蝇中的作用，我们失活DSiaT在体内的基因靶向和分析表型的DSiaT突变体的行为，免疫标记，电生理和药理学方法的组合。我们的实验表明，DSiaT的表达仅限于一个子集的中枢神经系统神经元在整个发展。我们发现DSiaT突变导致寿命显著缩短、运动异常、温度敏感性麻痹和神经肌肉接头缺陷。我们的研究结果表明，DSiaT调节神经元的兴奋性，并影响电压门控钠通道的功能。最后，我们发现唾液酸转移酶活性是DSiaT体内功能所必需的，这表明DSiaT突变体表型是由N-聚糖的唾液酸化缺陷引起的。这项工作提供了第一个证据表明唾液酸化在原口动物中具有重要的生物学功能，同时也揭示了α 2，6唾液酸化的一种新的神经系统特异性功能。因此，我们的数据揭示了唾液酸在后生动物中最古老的功能之一，并表明这种功能在苍蝇和哺乳动物之间进化上保守的可能性。
In vertebrates, sialylated glycans participate in a wide range of biological processes and affect nervous system’s development and function. While the complexity of glycosylation and the functional redundancy among sialyltransferases provide obstacles for revealing biological roles of sialylation in mammals, Drosophila possesses a sole vertebrate-type sialyltransferase, DSiaT, with significant homology to its mammalian counterparts, suggesting that Drosophila could be a suitable model to investigate the function of sialylation. To explore this possibility and investigate the role of sialylation in Drosophila, we inactivated DSiaT in vivo by gene targeting and analyzed phenotypes of DSiaT mutants using a combination of behavioural, immunolabeling, electrophysiological and pharmacological approaches. Our experiments demonstrated that DSiaT expression is restricted to a subset of CNS neurons throughout development. We found that DSiaT mutations result in significantly decreased life span, locomotor abnormalities, temperature-sensitive paralysis and defects of neuromuscular junctions. Our results indicate that DSiaT regulates neuronal excitability and affects the function of a voltage-gated sodium channel. Finally, we showed that sialyltransferase activity is required for DSiaT function in vivo, which suggests that DSiaT mutant phenotypes result from a defect in sialylation of N-glycans. This work provided the first evidence that sialylation has an important biological function in protostomes, while also revealing a novel, nervous system-specific function of α2,6 sialylation. Thus, our data shed light on one of the most ancient functions of sialic acids in metazoan organisms and suggest a possibility that this function is evolutionarily conserved between flies and mammals.