2012年9月27日 訊 /生物谷BIOON/ --在一項(xiàng)新的研究中,，美國(guó)德拉華大學(xué)電子與計(jì)算機(jī)工程助理教授Abhyudai Singh描述了一種新方法來(lái)理解基因表達(dá)中“噪音”的來(lái)源,，其中這種噪音使得蛋白水平發(fā)生變化。相關(guān)研究結(jié)果于近期刊登在Molecular Systems Biology期刊上,。
理解哪些生物化學(xué)過(guò)程導(dǎo)致這種變化是一個(gè)重要的問(wèn)題,，這是因?yàn)榈鞍鬃兓l(fā)揮著重要的作用，比如促進(jìn)遺傳上完全相同的細(xì)胞產(chǎn)生不同的細(xì)胞,，以及讓細(xì)胞群體對(duì)抗它們環(huán)境中發(fā)生的不可預(yù)測(cè)的有害變化,。
這種方法利用單個(gè)細(xì)胞內(nèi)的蛋白水平變化來(lái)精確地發(fā)現(xiàn)基因表達(dá)噪音的主要來(lái)源。
通過(guò)與來(lái)自美國(guó)加州大學(xué)舊金山分校格拉斯通病毒學(xué)與免疫學(xué)研究所的Leor Weinberger教授研究團(tuán)隊(duì)合作,，Singh將這種方法應(yīng)用到人免疫缺陷病毒(HIV)系統(tǒng),，在這種系統(tǒng)中，基因表達(dá)噪音能夠促進(jìn)HIV病毒進(jìn)入潛伏期,，即一種休眠的耐藥狀態(tài),。
這些結(jié)果揭示在HIV感染人細(xì)胞期間，mRNA復(fù)制的隨機(jī)性突增導(dǎo)致關(guān)鍵性病毒調(diào)節(jié)蛋白水平發(fā)生變化,。Singh說(shuō),，“我們認(rèn)為理解這種病毒基因表達(dá)噪聲的來(lái)源將在設(shè)計(jì)阻止HIV病毒進(jìn)入潛伏期的療法中產(chǎn)生重要的影響。”(生物谷：Bioon.com)
doi: 10.1038/msb.2012.38
PMC:
PMID:
Dynamics of protein noise can distinguish between alternate sources of gene-expression variability
Abhyudai Singh1,2,a, Brandon S Razooky1,3,4,a, Roy D Dar4,5 & Leor S Weinberger
Within individual cells, two molecular processes have been implicated as sources of noise in gene expression: (i) Poisson fluctuations in mRNA abundance arising from random birth and death of individual mRNA transcripts or (ii) promoter fluctuations arising from stochastic promoter transitions between different transcriptional states. Steady-state measurements of variance in protein levels are insufficient to discriminate between these two mechanisms, and mRNA single-molecule fluorescence in situ hybridization (smFISH) is challenging when cellular mRNA concentrations are high. Here, we present a perturbation method that discriminates mRNA birth/death fluctuations from promoter fluctuations by measuring transient changes in protein variance and that can operate in the regime of high molecular numbers. Conceptually, the method exploits the fact that transcriptional blockage results in more rapid increases in protein variability when mRNA birth/death fluctuations dominate over promoter fluctuations. We experimentally demonstrate the utility of this perturbation approach in the HIV-1 model system. Our results support promoter fluctuations as the primary noise source in HIV-1 expression. This study illustrates a relatively simple method that complements mRNA smFISH hybridization and can be used with existing GFP-tagged libraries to include or exclude alternate sources of noise in gene expression.
