細(xì)菌mRNA轉(zhuǎn)錄后的擴(kuò)散

由于在細(xì)菌被膜封閉的腔室中沒有進(jìn)行區(qū)隔，因此難以確定成熟信使RNA（mRNA）是怎樣在細(xì)胞內(nèi)分布的。Llopis等人利用熒光實(shí)驗(yàn)（這種實(shí)驗(yàn)很難做，因?yàn)榧?xì)菌太小）來跟蹤轉(zhuǎn)錄后mRNA的擴(kuò)散。他們發(fā)現(xiàn)，出人意料的是，新轉(zhuǎn)錄的mRNA所表現(xiàn)出的擴(kuò)散很有限。

Eukaryotic cells spatially organize mRNA processes such as translation and mRNA decay. Much less is clear in bacterial cells where the spatial distribution of mature mRNA remains ambiguous. Using a sensitive method based on quantitative fluorescence in situ hybridization, we show here that in Caulobacter crescentus and Escherichia coli, chromosomally expressed mRNAs largely display limited dispersion from their site of transcription during their lifetime. We estimate apparent diffusion coefficients at least two orders of magnitude lower than expected for freely diffusing mRNA, and provide evidence in C. crescentus that this mRNA localization restricts ribosomal mobility. Furthermore, C. crescentus RNase E appears associated with the DNA independently of its mRNA substrates. Collectively, our findings show that bacteria can spatially organize translation and, potentially, mRNA decay by using the chromosome layout as a template.

他們猜測，堆積的染色體材料可能自己充當(dāng)了一個區(qū)隔，來將轉(zhuǎn)錄與 mRNA降解分開。