Nature：李斯特菌从腐生菌转化为致病菌的奥秘
单核增生李斯特菌（Listeria monocytogenes）是一种常见的土壤细菌，在土壤中它是一种腐生菌，以死亡的和正在腐烂的有机物为食。它也是某些食物（主要是鲜奶产品）中的一种污染物，能引起严重食物中毒。
关于在一系列不同生长条件下单核增生李斯特菌转录组（细胞中的全部mRNA转录体）的一项新的研究，搞清了从腐生到致病生活方式的这种转变的性质。该研究的数据显示了一个转录程序，其复杂程度出乎意料，它涉及50个非编码RNA，同时还有一系列新的调控RNA，包括几个长反义RNA。在感染过程中，李斯特菌通过协调的全组转录变化成功重塑其转录程序，其中某些非编码RNA优先在小肠或血液中生长的细胞中表达。（生物谷Bioon.com）
生物谷推荐原始出处：
Nature 459, 950-956 (18 June 2009) | doi:10.1038/nature08080
The Listeria transcriptional landscape from saprophytism to virulence
Alejandro Toledo-Arana1,2,3,12, Olivier Dussurget1,2,3, Georgios Nikitas2,4,5, Nina Sesto1,2,3, Hélène Guet-Revillet1,2,3, Damien Balestrino1,2,3, Edmund Loh6,7, Jonas Gripenland6,7, Teresa Tiensuu6,7, Karolis Vaitkevicius6,7, Mathieu Barthelemy8, Massimo Vergassola9,10, Marie-Anne Nahori1,2,3, Guillaume Soubigou8, Béatrice Régnault8, Jean-Yves Coppée8, Marc Lecuit2,4,5,11, J?rgen Johansson6,7 & Pascale Cossart1,2,3
1 Institut Pasteur, Unité des Interactions Bactéries-Cellules, F-75015 Paris, France
2 Inserm, U604, F-75015 Paris, France
3 INRA, USC2020, F-75015 Paris, France
4 Institut Pasteur, G5 Microorganismes et Barrières de l'h?te, F-75015 Paris, France
5 Inserm, Avenir, U604, F-75015 Paris, France
6 Department of Molecular Biology,
7 The Laboratory for Molecular Infection Medicine Sweden (MIMS), Ume? University, S-90187 Ume?, Sweden
8 Institut Pasteur, Génopole, Plate-forme 2, F-75015 Paris, France
9 Institut Pasteur, UP Génétique in silico, F-75015 Paris, France
10 CNRS, URA2171, F-75015 Paris, France
11 Université Paris Descartes, H?pital Necker-Enfants malades, Assistance Publique-H?pitaux de Paris, Paris, F-75015 France
12 Present address: Instituto de Agrobiotecnología, Universidad Pública de Navarra-CSIC-Gobierno de Navarra, 31006-Pamplona, Spain.
The bacterium Listeria monocytogenes is ubiquitous in the environment and can lead to severe food-borne infections. It has recently emerged as a multifaceted model in pathogenesis. However, how this bacterium switches from a saprophyte to a pathogen is largely unknown. Here, using tiling arrays and RNAs from wild-type and mutant bacteria grown in vitro, ex vivo and in vivo, we have analysed the transcription of its entire genome. We provide the complete Listeria operon map and have uncovered far more diverse types of RNAs than expected: in addition to 50 small RNAs (<500 nucleotides), at least two of which are involved in virulence in mice, we have identified antisense RNAs covering several open-reading frames and long overlapping 5' and 3' untranslated regions. We discovered that riboswitches can act as terminators for upstream genes. When Listeria reaches the host intestinal lumen, an extensive transcriptional reshaping occurs with a SigB-mediated activation of virulence genes. In contrast, in the blood, PrfA controls transcription of virulence genes. Remarkably, several non-coding RNAs absent in the non-pathogenic species Listeria innocua exhibit the same expression patterns as the virulence genes. Together, our data unravel successive and coordinated global transcriptional changes during infection and point to previously unknown regulatory mechanisms in bacteria.