Growth-blocking peptide expressed in the insect nervous system--cloning and functional characterization.
Growth-blocking peptide expressed in the insect nervous system--cloning and functional characterization.
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昆虫神经系统中表达的生长阻断肽——克隆和功能表征。
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
H. Noguchi
中科院分区：
文献类型：
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作者：
Y. Hayakawa;H. Noguchi
生长阻断肽 (GBP) 是一种昆虫生物肽，可延缓幼虫生长，从而延迟鳞翅目幼虫化蛹的开始。 GBP 基因的转录已被证明以组织依赖性方式受到脂肪体中约 0.8-kb mRNA 转录物和大脑中枢神经系统 (CNS) 中 2.5-kb 转录物的调节 [Hayakawa, Y., Ohnishi, A., Yamanaka, A., Izumi, S. & Tomino, S. (1995) FEBS Lett. 367、185-189]。分离并测序了大脑CNS中的GBP cDNA，发现其与脂肪体中的GBP cDNA几乎相同，只是它编码了一个长的5'非翻译区（约1.1 kb），这表明大脑CNS是作为多蛋白前体合成的，并以与脂肪体中预测的相同方式通过翻译后加工释放。基因组 GBP 基因片段的序列分析表明，5'-非翻译区包含一个编码序列元件 TGATAA 的内含子，据报道该元件对于昆虫幼虫脂肪体中的表达很重要，表明该元件有助于脂肪体中较短 GBP mRNA 的组织特异性表达。核糖核酸酶保护测定表明，寄生黄蜂的寄生提高了脑中枢神经系统中 GBP mRNA 的表达。寄生引起的 GBP 前体和 GBP 浓度的增加也在脑中枢神经系统中得到证实。将组织与 GBP 一起孵育 8 小时，通过转录增强提高多巴脱羧酶活性，脑中枢神经系统多巴胺增加八倍，这可能是由于 GBP 诱导的细胞质 Ca2+ 浓度增加所致。多巴胺升高减少了蛋氨酸体外掺入脑中枢神经系统合成的蛋白质。
Growth-blocking peptide (GBP) is an insect biogenic peptide that retards larval growth and, consequently, delays the onset of pupation of lepidopteran larvae. Transcription of the GBP gene has been proven to be regulated in a tissue-dependent manner by an approximately 0.8-kb mRNA transcript in fat body and 2.5-kb transcript in the brain central nervous system (CNS) [Hayakawa, Y., Ohnishi, A., Yamanaka, A., Izumi, S. & Tomino, S. (1995) FEBS Lett. 367, 185-189]. The GBP cDNA in the brain CNS was isolated, sequenced and found to be almost identical with that in the fat body, except that it encodes a long 5'-untranslated region (approximately 1.1 kb), thus indicating that the brain CNS is synthesized as a polyprotein precursor and released through posttranslational processing in the same manner as that predicted in the fat body. Sequence analyses of the genomic GBP gene fragments demonstrated that the 5'-untranslated region contains an intron encoding a sequence element, TGATAA, which has been reported to be important for expression in the insect larval fat body, suggesting that this element contributes to a tissue-specific expression of the shorter GBP mRNA in fat body. Ribonuclease protection assays showed that parasitization by a parasitic wasp elevated the expression of GBP mRNA in brain CNS. The parasitization-induced increase of GBP precursor and GBP concentrations was also demonstrated in brain CNS. Brain CNS dopamine was increased eightfold by incubating the tissue with GBP for 8 h through the elevation of dopa decarboxylase activity by a transcriptional enhancement perhaps due to GBP-induced increase of cytoplasmic Ca2+ concentration. Dopamine elevation reduced in vitro incorporation of methionine into proteins synthesized in brain CNS.