Excess melanin precursors rescue defective cuticular traits in stony mutant silkworms probably by upregulating four genes encoding RR1-type larval cuticular proteins
Excess melanin precursors rescue defective cuticular traits in stony mutant silkworms probably by upregulating four genes encoding RR1-type larval cuticular proteins
复制标题
过量的黑色素前体可能通过上调编码 RR1 型幼虫角质层蛋白的四个基因来挽救石突变蚕的缺陷角质层特征
DOI：
10.1016/j.ibmb.2020.103315
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发表时间：
2020
影响因子：
3.8
通讯作者：
Dai Fang-yin
中科院分区：
文献类型：
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作者：
Qiao Liang;Yan Zheng-Wen;Xiong Gao;Hao You-jin;Wang Ri-xin;Hu Hai;Song Jiang-bo;Tong Xiao-ling;Che Lin-rong;He Song-zhen;Chen Bin;Mallet James;Lu Cheng;Dai Fang-yin
黑色素和角质层蛋白是昆虫体内重要的角质层成分。由角质蛋白编码基因突变引起的角质层缺陷会阻碍黑色素沉积。黑色素的变化对角质层蛋白编码基因的表达、角质层和形态特征的影响以及这些影响的来源尚不清楚。我们发现，幼虫的角质层物理特征和角质层蛋白编码基因的表达模式在黑色素区和非黑色素区明显不同。利用黑化程度递增的4个多等位基因(+p、pm、ps和pB)，我们发现黑化程度与4个RR1型幼虫角质蛋白编码基因(BmCPR2、BmLcp18、BmLcp22和BmLcp30)的表达呈正相关。通过调节黑色素前体的含量和角质层蛋白编码基因在组织和体内细胞中的表达，我们表明这种正相关是由于黑色素前体的诱导。更重要的是，导入BmCPR2缺失品系大枣的黑色素特性诱导了另外三个类似的甲壳素结合特征幼虫角质层蛋白编码基因的上调，从而挽救了大枣品系的角质层、形态和适应性缺陷。这种救援能力随着黑化程度的增加而增强。这是第一次报道黑色素诱导角质层蛋白编码基因的研究，以及这种诱导在影响角质层生理特征方面的生物学重要性。
Melanin and cuticular proteins are vital cuticle components in insects. Cuticular defects caused by mutations in cuticular protein-encoding genes can obstruct melanin deposition. The effects of changes in melanin on the expression of cuticular protein-encoding genes, the cuticular and morphological traits, and the origins of these effects are unknown. We found that the cuticular physical characteristics and the expression patterns of larval cuticular protein-encoding genes markedly differed between the melanic and non-melanic integument regions. By using fourpmultiple-allele color pattern mutants with increasing degrees of melanism (+p,pM,pS, andpB), we found that the degree of melanism and the expression of four RR1-type larval cuticular protein-encoding genes (BmCPR2,BmLcp18,BmLcp22, andBmLcp30) were positively correlated. By modulating the content of melanin precursors and the expression of cuticular protein-encoding genes in cells in tissues andin vivo, we showed that this positive correlation was due to the induction of melanin precursors. More importantly, the melanism trait introduced into theBmCPR2deletion strain Dazao-stonyinduced up-regulation of three other similar chitin-binding characteristic larval cuticular protein-encoding genes, thus rescuing the cuticular, morphological and adaptability defects of the Dazao-stonystrain. This rescue ability increased with increasing melanism levels. This is the first study reporting the induction of cuticular protein-encoding genes by melanin and the biological importance of this induction in affecting the physiological characteristics of the cuticle.