期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2015
卷号：112
期号：17
页码：5389-5394
DOI：10.1073/pnas.1419264112
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceThe cyclic dinucleotides c-di-GMP and c-di-AMP are responsible for controlling broad changes in cell phenotypes during the life cycles of many bacterial species. To date, riboswitches that sense c-di-GMP and c-di-AMP have been discovered. The genomic locations of riboswitches reveal numerous genes that are controlled by these signaling compounds and thereby reveal the biological processes that are regulated. Herein, we report that a subset of conserved noncoding RNA domains previously annotated as c-di-GMP-I riboswitches in fact bind the newly discovered second messenger c-AMP-GMP. These riboswitches control many genes involved in the utilization of extracellular iron(III) oxide as an electron sink by various Geobacter species. Our findings reveal additional roles for this recently discovered signaling molecule. Major changes in bacterial physiology including biofilm and spore formation involve signaling by the cyclic dinucleotides c-di-GMP and c-di-AMP. Recently, another second messenger dinucleotide, c-AMP-GMP, was found to control chemotaxis and colonization by Vibrio cholerae. We have identified a superregulon of genes controlled by c-AMP-GMP in numerous Deltaproteobacteria, including Geobacter species that use extracellular insoluble metal oxides as terminal electron acceptors. This exoelectrogenic process has been studied for its possible utility in energy production and bioremediation. Many genes involved in adhesion, pilin formation, and others that are important for exoelectrogenesis are controlled by members of a variant riboswitch class that selectively bind c-AMP-GMP. These RNAs constitute, to our knowledge, the first known specific receptors for c-AMP-GMP and reveal that this molecule is used by many bacteria to control specialized physiological processes.
关键词：riboswitch ; Geobacter ; GEMM ; c-di-GMP ; second messenger
