Li Kang, Guo Enen, Hossain Muktadir S, Li Qingrong, Cao Yang, Tian Ling, Deng Xiaojuan, Li Sheng
1] Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding/Guangdong Provincial Sericulture and Mulberry Engineering Research Center, College of Animal Sciences, South China Agricultural University, Guangzhou, 510642, China [2] Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
Sci Rep. 2015 Jul 13;5:12114. doi: 10.1038/srep12114.
Resulted from alternative splicing of the 5' exons, the nuclear receptor gene E75 in the silkworm, Bombyx mori, processes three mRNA isoforms, BmE75A, BmE75B and BmE75C. From the early 5(th) larval instar to the prepupal stages, BmE75A mRNA and protein levels in the prothoracic glands display developmental profiles similar to ecdysteroid titer. In the fat body, mRNA levels but not protein levels of all three BmE75 isoforms correlate with ecdysteroid titer; moreover, proteins of all three BmE75 isoforms disappear at the prepupal stages, and a modified BmE75 protein with smaller molecular weight and cytoplasm localization occurs. At the early 5(th) larval instar stage, treatment of the prothoracic glands and fat body with 20-hydroxyecdysone (20E) and/or cycloheximide (CHX) revealed that BmE75A is 20E primary-responsive at both mRNA and protein levels, while BmE75B and BmE75C exhibit various responses to 20E. At the early wandering stage, RNAi-mediated reduction of gene expression of the 20E nuclear receptor complex, EcR-USP, significantly decreased mRNA and protein levels of all three BmE75 isoforms in both tissues. In conclusion, BmE75 isoforms display stage- and tissue-specific responses to 20E at both mRNA and protein levels; moreover, they are regulated by other unknown factors at the protein level.
家蚕核受体基因E75的5'外显子可变剪接产生了三种mRNA亚型，即BmE75A、BmE75B和BmE75C。从5龄幼虫早期到蛹前期，前胸腺中BmE75A的mRNA和蛋白质水平呈现出与蜕皮甾体滴度相似的发育模式。在脂肪体中，所有三种BmE75亚型的mRNA水平而非蛋白质水平与蜕皮甾体滴度相关；此外，所有三种BmE75亚型的蛋白质在蛹前期消失，出现了一种分子量较小且定位于细胞质的修饰型BmE75蛋白。在5龄幼虫早期阶段，用20-羟基蜕皮酮（20E）和/或环己酰亚胺（CHX）处理前胸腺和脂肪体，结果显示BmE75A在mRNA和蛋白质水平上都是20E的主要应答基因，而BmE75B和BmE75C对20E表现出不同的应答。在化蛹前期，RNA干扰介导的20E核受体复合物EcR-USP基因表达降低显著降低了两个组织中所有三种BmE75亚型的mRNA和蛋白质水平。总之，BmE75亚型在mRNA和蛋白质水平上对20E表现出阶段和组织特异性应答；此外，它们在蛋白质水平上还受其他未知因素的调控。
