朊蛋白一向都與臭名昭著的瘋牛病聯(lián)系在一起，提起朊蛋白就不得不讓人想起瘋牛病,，假如您有這樣的想法,，今天一篇Cell文章可能會(huì)改變您對(duì)朊蛋白的看法,，來自白頭研究所和霍華休斯研究所的科學(xué)家發(fā)現(xiàn)酵母的朊蛋白具有促進(jìn)酵母適應(yīng)環(huán)境變化的功能，所以說,，朊蛋白并非一無是處,，它也有好的一面。
西北大學(xué)研究酵母朊蛋白的生物化學(xué)家Liming Li說,，這項(xiàng)研究成果令人著迷,，并且具有重要的生物學(xué)意義。這些研究結(jié)果甚至表明朊蛋白在表觀遺傳學(xué)中起重要的作用,，對(duì)基因表達(dá)的調(diào)控有重要的意義,。
該文章的通訊作者白頭研究所的分子生物學(xué)家Susan Lindquist表示,，在先前的研究中,，科學(xué)家們已經(jīng)發(fā)現(xiàn)在酵母中有3-4個(gè)蛋白是朊蛋白，因此她和同事希望能深入篩選,，找找酵母中的其他朊蛋白,。于是她們?cè)陔玫鞍赘患幕蚪M區(qū)域內(nèi)尋找朊蛋白的信息，結(jié)果找出200余種符合阮蛋白標(biāo)準(zhǔn)的序列,。
這一結(jié)果表明酵母細(xì)胞內(nèi)的朊蛋白的含量遠(yuǎn)比之前假設(shè)的要多,。有些甚至出現(xiàn)的頻率十分高，研究人員懷疑朊蛋白對(duì)酵母的正常機(jī)能的維持具有重要的作用,。她們分析了Mot3,，結(jié)果發(fā)現(xiàn)正常的Mot3能幫助酵母構(gòu)建完整的柔軟的細(xì)胞壁，而發(fā)生突變的Mot3會(huì)導(dǎo)致酵母細(xì)胞壁變得僵硬,。
在正常的情況小,，酵母需要一個(gè)柔軟的細(xì)胞壁，這樣有助它快速地分裂繁殖,，如果細(xì)胞壁變得僵硬會(huì)抑制酵母細(xì)胞分化生長(zhǎng),。
研究者猜測(cè)，朊蛋白的這一情況不僅存在于酵母中,，在其他生命體中朊蛋白也許也具有重要的功能和作用,。作者之一Halfmann稱，他們將在下一步對(duì)其他生命體的朊蛋白進(jìn)行研究,。（生物谷Bioon.com）
生物谷推薦原始出處：
Cell, 3 April 2009 doi:10.1016/j.cell.2009.02.044
A Systematic Survey Identifies Prions and Illuminates Sequence Features of Prionogenic Proteins
Simon Alberti1,5,Randal Halfmann1,3,5,Oliver King1,4,Atul Kapila1,3andSusan Lindquist1,2,3,,
1 Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
2 Howard Hughes Medical Institute, Cambridge, MA 02139, USA
3 Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
4 Boston Biomedical Research Institute, Watertown, MA 02472, USA
5 These authors contributed equally to this work
Prions are proteins that convert between structurally and functionally distinct states, one or more of which is transmissible. In yeast, this ability allows them to act as non-Mendelian elements of phenotypic inheritance. To further our understanding of prion biology, we conducted a bioinformatic proteome-wide survey for prionogenic proteins in S. cerevisiae, followed by experimental investigations of 100 prion candidates. We found an unexpected amino acid bias in aggregation-prone candidates and discovered that 19 of these could also form prions. At least one of these prion proteins, Mot3, produces a bona fide prion in its natural context that increases population-level phenotypic heterogeneity. The self-perpetuating states of these proteins present a vast source of heritable phenotypic variation that increases the adaptability of yeast populations to diverse environments.
