Effects of starvation and hormones on DNA synthesis in silk gland cells of the silkworm, Bombyx mori
Effects of starvation and hormones on DNA synthesis in silk gland cells of the silkworm, Bombyx mori
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饥饿和激素对家蚕丝腺细胞 DNA 合成的影响
DOI：
10.1111/1744-7917.12199
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发表时间：
2016-08-01
期刊：
影响因子：
4
通讯作者：
Lu, Cheng
中科院分区：
文献类型：
--
作者：
Li, Yao-Feng;Chen, Xiang-Yun;Lu, Cheng
家蚕幼虫的丝腺细胞在纺丝期为合成丝蛋白而经历了多个周期的内丝分裂。本文对蚕丝腺细胞在幼虫发育过程中的线粒体DNA合成进行了分析，发现蚕丝腺细胞的DNA合成呈周期性波动，在旺盛的摄食期增加，在下一个蜕皮期逐渐被抑制。这意味着它可能是在蜕皮后通过自我调节过程激活的。细胞周期蛋白E、cdt1和pcna的表达水平与这些发育变化一致。此外，我们进一步研究了这些线粒体DNA合成的变化是否由喂养或激素刺激引起。结果表明，饥饿可以抑制DNA合成，再喂食可以激活DNA合成，因此DNA合成可能依赖于营养。20 -羟基蜕皮激素（20E）在体内抑制DNA合成。然而，体外20E处理和体内、体外少年激素处理对DNA合成均无影响。饥饿和体内20E处理也降低了丝腺中Akt和4E‐BP磷酸化水平。这些结果表明，脱毛期线粒体DNA合成的激活与摄食有关，20E间接抑制了DNA合成。
Silk gland cells of silkworm larvae undergo multiple cycles of endomitosis for the synthesis of silk proteins during the spinning phase. In this paper, we analyzed the endomitotic DNA synthesis of silk gland cells during larval development, and found that it was a periodic fluctuation, increasing during the vigorous feeding phase and being gradually inhibited in the next molting phase. That means it might be activated by a self‐regulating process after molting. The expression levels of cyclin E, cdt1 and pcna were consistent with these developmental changes. Moreover, we further examined whether these changes in endomitotic DNA synthesis resulted from feeding or hormonal stimulation. The results showed that DNA synthesis could be inhibited by starvation and re‐activated by re‐feeding, and therefore appears to be dependent on nutrition. DNA synthesis was suppressed by in vivo treatment with 20‐hydroxyecdysone (20E). However, there was no effect on DNA synthesis by in vitro 20E treatment or by either in vivo or in vitro juvenile hormone treatment. The levels of Akt and 4E‐BP phosphorylation in the silk glands were also reduced by starvation and in vivo treatment with 20E. These results indicate that the activation of endomitotic DNA synthesis during the intermolt stages is related to feeding and DNA synthesis is inhibited indirectly by 20E.