Molecular characterization of a cDNA encoding extracellular dsRNase and its expression in the silkworm, Bombyx mori
Molecular characterization of a cDNA encoding extracellular dsRNase and its expression in the silkworm, Bombyx mori
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DOI：
10.1016/j.ibmb.2006.11.004
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发表时间：
2007-02-01
影响因子：
3.8
通讯作者：
Furusawa, Toshiharu
中科院分区：
文献类型：
--
作者：
Arimatsu, Yuji;Kotani, Eiji;Furusawa, Toshiharu
从家蚕幼虫消化液中分离到一种双链核糖核酸酶(BM-dsRNase)。根据BM-dsRNase的N端序列设计了一条20聚体的引物，扩增出全长cDNA，并进行了测序。该基因编码51 kDa的前体蛋白，分为三个结构域：信号肽、N-末端前肽和成熟的BM-dsRNase。前体含有Arg-Ser裂解位点，通过翻译后加工产生43 kDa的成熟蛋白。43 kDa的蛋白质含有保守的催化氨基酸残基，这些残基也存在于粘质沙雷氏菌dsRNase的活性部位。从5龄幼虫第1天开始，该前体在中肠的中后部组织中开始表达。从第2天起，43 kDa的蛋白质就在这个组织中产生，并巧合地分泌到含有消化液的管腔中。免疫组织化学观察到，成熟蛋白定位于中肠细胞顶端，用于细胞外分泌，支持这一点。(C)2006爱思唯尔有限公司。保留所有权利。
A double-stranded ribonuclease (Bm-dsRNase) was separated from the digestive juice of the silkworm larvae, Bombyx mori. The full-length cDNA was produced and sequenced using a 20mer primer designed from the N-terminal sequence of the Bm-dsRNase. The cDNA had an ORF encoding 51 kDa precursor protein which can be divided into three domains: a signal peptide, an N-terminal propeptide and a mature Bm-dsRNase. The precursor has an Arg-Ser cleavage site, which produces the 43 kDa mature protein by post-translational processing. The 43 kDa protein had conserved catalytic amino acid residues which are also found in the active site of the Serratia marcescens dsRNase. Expression of the precursor occurred in the middle and posterior midgut tissues, starting from Day 1 of the fifth instar larvae. The 43 kDa protein was produced in this tissue from Day 2, and coincidentally secreted into the lumen containing digestive juice. This was supported by the immunohistochemical observation that the mature proteins were localized in the apical side of midgut cells for extracellular secretion. (c) 2006 Elsevier Ltd. All rights reserved.