Department of Biology, Indiana University, Bloomington, IN 47405, USA.
Science. 2010 May 21;328(5981):993. doi: 10.1126/science.1187200.
Small RNA (sRNA) molecules regulate a vast array of processes in biology, but evidence for adaptive evolution of sRNA sequences has been indirect. Here, we identify an sRNA, Pxr, that negatively regulates fruiting body development in Myxococcus xanthus. We further show that a spontaneous evolutionary mutation in Pxr abolished its regulatory function and thereby adaptively restored developmental proficiency to a socially defective M. xanthus cheater. In wild-type M. xanthus, development is initiated only upon starvation, but deletion of pxr allows development to proceed even while nutrients remain abundant. Thus, Pxr serves as a major checkpoint controlling the transition from growth to development in the myxobacteria. These findings show that an sRNA molecule governs a complex form of multicellular development in prokaryotes and directly demonstrate the ability of sRNA regulators to facilitate evolutionary adaptations of major phenotypic effect.
小 RNA (sRNA) 分子调节生物学中的众多过程，但 sRNA 序列适应性进化的证据一直是间接的。在这里，我们鉴定出一个 sRNA 分子 Pxr，它负调控粘细菌 Myxococcus xanthus 中 子实体的发育。我们进一步表明，Pxr 中的一个自发进化突变使其丧失了调节功能，从而使社会缺陷型 M. xanthus 骗子恢复了发育能力。在野生型 M. xanthus 中，只有在饥饿时才会启动发育，但 pxr 的缺失允许即使在营养丰富的情况下也能进行发育。因此，Pxr 作为一个主要的检查点，控制着从生长到发育的过渡。这些发现表明，sRNA 分子控制着原核生物中复杂形式的多细胞发育，并直接证明了 sRNA 调节剂促进主要表型效应的进化适应的能力。
