當(dāng)細(xì)胞產(chǎn)生蛋白質(zhì)的過程中出現(xiàn)大量的錯(cuò)誤時(shí)，細(xì)胞的凋亡機(jī)制就會啟動,。但在凋亡啟動之前，細(xì)胞還可以通過一些細(xì)胞的“應(yīng)激應(yīng)答”來挽救一部分錯(cuò)誤,。最近,，巴塞羅那生物醫(yī)藥研究所設(shè)計(jì)了一項(xiàng)新方法,，該方法可以用來深入研究細(xì)胞營救的信號通路和細(xì)胞的凋亡機(jī)制。這項(xiàng)研究發(fā)表在最新的Journal Nucleic Acids Research雜志上,。
傳統(tǒng)的技術(shù)是使用藥物或某些化合物來干擾蛋白質(zhì)合成的機(jī)器,，從而產(chǎn)生大量的缺陷型蛋白，當(dāng)細(xì)胞積累了大量的錯(cuò)誤折疊蛋白后,，細(xì)胞的報(bào)警系統(tǒng)被打開,，細(xì)胞應(yīng)激應(yīng)答被激活。通過這種方法,，研究人員可以觀察到整個(gè)反應(yīng)中的所有步驟,。
在蛋白質(zhì)的生產(chǎn)過程中，轉(zhuǎn)運(yùn)RNA(tRNA)起重要作用,，能夠?qū)⒌鞍踪|(zhì)合成過程中所需的氨基酸添加到蛋白質(zhì)序列的合適的位置,。該課題組設(shè)計(jì)了一類與天然tRNAs十分相似的全新的tRNAs，但這種tRNAs是將錯(cuò)誤的氨基酸加到蛋白質(zhì)序列中,，從而導(dǎo)致細(xì)胞產(chǎn)生大量的缺陷型蛋白質(zhì)，從而激活細(xì)胞的應(yīng)激應(yīng)答,，該過程不需要引入外援的藥物和化合物,，可以使研究人員觀察到細(xì)胞何時(shí)通過何種方式進(jìn)入細(xì)胞的凋亡過程。
課題組通過分析表明,，當(dāng)細(xì)胞內(nèi)積累了大量的錯(cuò)誤折疊蛋白后,，細(xì)胞還能產(chǎn)生一類能夠調(diào)控基因表達(dá)的micro-RNAs。但目前為止,，研究人員還不清楚這類micro-RNAs是如何調(diào)控基因表達(dá)過程的,。（生物谷Bioon.com）
生物谷推薦原始出處：
Nucleic Acids Research, doi:10.1093/nar/gkp1083
Chimeric tRNAs as tools to induce proteome damage and identify components of stress responses
Renaud Geslain1, Laia Cubells1, Teresa Bori-Sanz2, Roberto álvarez-Medina3, David Rossell1, Elisa Martí3 and Lluís Ribas de Pouplana1,4,*
1Institute for Research in Biomedicine (IRB), 2Omnia Molecular, Barcelona Science Park, 3Instituto de Biología Molecular de Barcelona, CSIC, Parc Cientific de Barcelona, c/Baldiri Reixac 15-21, Barcelona 08028 and 4Catalan Institution for Research and Advanced Studies (ICREA), Passeig Lluís Companys 23, 08010 Barcelona, Spain
Misfolded proteins are caused by genomic mutations, aberrant splicing events, translation errors or environmental factors. The accumulation of misfolded proteins is a phenomenon connected to several human disorders, and is managed by stress responses specific to the cellular compartments being affected. In wild-type cells these mechanisms of stress response can be experimentally induced by expressing recombinant misfolded proteins or by incubating cells with large concentrations of amino acid analogues. Here, we report a novel approach for the induction of stress responses to protein aggregation. Our method is based on engineered transfer RNAs that can be expressed in cells or tissues, where they actively integrate in the translation machinery causing general proteome substitutions. This strategy allows for the introduction of mutations of increasing severity randomly in the proteome, without exposing cells to unnatural compounds. Here, we show that this approach can be used for the differential activation of the stress response in the Endoplasmic Reticulum (ER). As an example of the applications of this method, we have applied it to the identification of human microRNAs activated or repressed during unfolded protein stress.
