The silkworm is an economically important insect producing plentiful silk fibre in the silk gland. In this study, we reported a cross‐talk between the fat body, silk gland and midgut through a glycine‐serine biosynthetic pathway in the silkworm. Amino acid sequence and functional domains of glycine transporter gene BmGT1‐L were mapped. Our results indicated that BmGT1‐L was specifically expressed in the midgut microvilli and persistently expressed during the feeding stages. RNA interference of BmGT1‐L activated glycine biosynthesis, and BmGT1‐L overexpression facilitated serine biosynthesis in the BmN4‐SID1 cell. In addition, silkworms after FibH gene knock‐out or silk gland extirpation showed markedly decreased BmGT1‐L transcripts in the midgut and disturbed glycine‐serine biosynthesis as silk yield decreased. Finally, BmGT1‐L ectopic expression in the posterior silk gland promoted glycine biosynthesis, and enhanced silk yield via increasing fibroin synthesis. These results suggested that cross‐talk between tissues can be used for enhancing silk yield in the silkworm.

中文翻译：

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通过在后部丝腺中异位表达BmGT1-L，提高了转基因家蚕（Bombyx mori）的丝产量。

蚕是一种经济上重要的昆虫，可在蚕丝腺中产生丰富的蚕丝纤维。在这项研究中，我们报道了蚕体内脂肪体，丝腺和中肠之间通过甘氨酸-丝氨酸生物合成途径发生串扰。绘制了甘氨酸转运蛋白基因BmGT1-L的氨基酸序列和功能域。我们的结果表明，BmGT1-L在中肠微绒毛中特异性表达，并在喂养阶段持续表达。BmGT1-L激活的甘氨酸生物合成的RNA干扰和BmGT1-L的过表达促进了BmN4-SID1细胞中丝氨酸的生物合成。此外，FibH之后的蚕基因敲除或丝腺切除显示中肠的BmGT1-L转录物显着减少，并且随着丝产量的降低，甘氨酸-丝氨酸的生物合成受到干扰。最后，后丝腺中BmGT1-L异位表达促进了甘氨酸的生物合成，并通过增加丝蛋白合成而提高了丝产量。这些结果表明，组织之间的串扰可用于提高家蚕的蚕丝产量。