BmSUC1 is essential for glycometabolism modulation in the silkworm, Bombyx mori
BmSUC1 is essential for glycometabolism modulation in the silkworm, Bombyx mori
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BmSUC1 对于家蚕 Bombyx mori 的糖代谢调节至关重要
DOI：
10.1016/j.bbagrm.2018.04.002
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发表时间：
2018-06-01
影响因子：
4.7
通讯作者：
Meng, Yan
中科院分区：
文献类型：
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作者：
Gan, Quan;Zhang, Xinwei;Meng, Yan
蔗糖是植物体内最常运输的糖，也是昆虫最容易吸收利用的糖，以满足其生理代谢的需要。BmSucl是一个新的动物β-呋喃果糖苷酶（beta-FFase，EC 3.2.1.26）编码基因，首次从家蚕中克隆并鉴定。推测BmSUC 1通过有效水解桑葚吸收的蔗糖，在家蚕-桑树酶适应系统中发挥重要作用。然而，迄今为止，这一点尚未得到直接证据的证明。本文研究了B幼虫中肠蔗糖水解活性。通过抑制试验发现，蔗糖酶活性主要来源于β-FFase，而不是α-葡萄糖苷酶。接下来，我们进行了shRNA介导的转基因RNA干涉，分析了转基因蚕幼虫的生长特性和体内糖代谢的变化。结果表明，转RNAi BmSucl基因的转基因株系，幼虫发育延迟，体尺显著缩小。最后，几个dispensidases单独在中肠的活性和糖的分布，总糖和糖原在中肠，血淋巴和脂肪体，然后测定和比较。我们的结果表明，沉默BmSucl显着降低葡萄糖和明显激活麦芽糖酶和海藻糖酶中肠。连同脂肪体中糖原和海藻糖的明显减少，我们得出结论，BmSUC 1作为一种必需的蔗糖酶，通过直接调节家蚕幼虫中肠中蔗糖水解的程度，脂肪体中糖储存不足可能是幼虫营养不良和异常娇小表型的原因。
Sucrose is the most commonly transported sugar in plants and is easily assimilated by insects to fulfill the requirement of physiological metabolism. BmSucl is a novel animal beta-fructofuranosidase (beta-FFase, EC 3.2.1.26) encoding gene that was firstly cloned and identified in silkworm, Bombyx mori. BmSUC1 was presumed to play an important role in the silkworm-mulberry enzymatic adaptation system by effectively hydrolyzing sucrose absorbed from mulberry leaves. However, this has not been proved with direct evidence thus far. In this study, we investigated sucrose hydrolysis activity in the larval midgut of B. mori by inhibition tests and found that sucrase activity mainly stemmed from beta-FFase, not a-glucosidase. Next, we performed shRNA-mediated trans genic RNAi to analyze the growth characteristics of silkworm larvae and variations in glycometabolism in vivo in transgenic silkworms. The results showed that in the RNAi-BmSucl transgenic line, larval development was delayed, and their body size was markedly reduced. Finally, the activity of several disaccharidases alone in the midgut and the sugar distribution, total sugar and glycogen in the midgut, hemolymph and fat body were then determined and compared. Our results demonstrated that silencing BmSucl significantly reduced glucose and apparently activated maltase and trehalase in the midgut. Together with a clear decrease in both glycogen and trehalose in the fat body, we conclude that BmSUC1 acts as an essential sucrase by directly modulating the degree of sucrose hydrolysis in the silkworm larval midgut, and insufficient sugar storage in the fat body may be responsible for larval malnutrition and abnormal petite phenotypes.