Denoising feedback loops by thresholding—a new role for microRNAs
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
This extract was created in the absence of an abstract.
It is almost axiomatic that precision in spatial and temporal control of gene expression is important for organogenesis. Our appreciation of this notion derives in part from studies of the developing sensory nervous system in Drosophila (for review, see Modolell 1997). In this issue of Genes & Development, Gao and coworkers (Li et al. 2006) add an exciting new twist to this story, showing that post-transcriptional gene regulation by the microRNA miR-9a plays an important role in ensuring the precision of sense organ specification in Drosophila.
microRNAs (miRNAs) have gained considerable attention recently as negative post-transcriptional regulators of gene expression (e.g., Ambros 2004; Bartel and Chen 2004; Zamore and Haley 2005; Valencia-Sanchez et al. 2006). miRNAs are an abundant class of noncoding RNAs in animals (Bartel 2004; Berezikov et al. 2005; Xie et al. 2005) and are predicted to target 30% or more of all animal protein coding genes (Brennecke et al. 2005; Grun et al. 2005; Krek et al. 2005; Lewis et al. 2005; Xie et al. 2005). Likewise, a large number of genes—the so-called anti-targets—are under evolutionary pressure to avoid target sites (Farh et al. 2005; Stark et al. 2005). The investigation of such target and anti-target signatures for miRNAs has recently led to the proposal that miRNAs confer robustness to gene expression (Stark et al. 2005; Hornstein and Shomron 2006), yet few definite functions have been assigned to individual miRNAs to date (Li and Carthew 2005; Krutzfeldt et al. 2005; Sokol and Ambros 2005; Giraldez et al. 2006; Teleman et al. 2006; pre-2005 work reviewed in Ambros 2004; Alvarez-Garcia and Miska 2005).
Li et al. (2006) now report on the function of miR-9a by generating a targeted …
