Biology Reference
In-Depth Information
6.1 miR-8
117
6.2 miR-959
964 cluster
117
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6.3 Bioinformatics predicts additional miRNAs involved in immune response
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7. Summary
118
References
118
Abstract
MicroRNAs (miRNAs) ensure progression through development by synchronizing cell
fate transitions in response to environmental cues. These cues are mediated at least
in part by steroid hormones. Emerging evidence indicates that miRNAs are also com-
ponents of additional systemic signaling pathways, including insulin, stress, immune,
and circadian pathways. Thus, the roles that miRNAs play during development are
reflected in their post-developmental functions, where they similarly function to coor-
dinate cell behavior in response to environmental cues. In this review, we summarize
current work highlighting the role of miRNAs in systemic signaling pathways in
Drosophila melanogaster as a way of synthesizing the underlying roles of miRNAs in both
animal developmental transitions and adult physiology.
1. INTRODUCTION
21-nucleotide (nt) noncoding
RNAs that regulate the stability and translation of target messenger RNAs
(mRNAs) and play essential roles in both animal development and physiol-
ogy (
Cohen, 2010; Mendell & Olson, 2012
). Forward genetic analysis of
Caenorhabditis elegans
identified the first members of this class of post-
transcriptional regulators,
lin-4
and
let-7
. These miRNAs are components
of the heterochronic pathway, which is a developmental signaling pathway
that ensures that cells adopt the appropriate stage-specific cell fates (for a
review of this pathway, see
chapter 6
by Rougvie and Moss in this volume).
In response to environmental cues, like food availability and population
density, steroid hormones activate miRNAs that repress cell fate determi-
nants. The heterochronic pathway functions in cell lineages throughout
the animal, synchronizing progression through developmental transitions
with environmental conditions.
Emerging evidence indicates that this function of heterochronic
miRNAs is evolutionarily conserved, and highlights a more general function
of miRNAs to coordinate cell behavior in response to environmental stim-
uli. We explore this evidence here, reviewing recent work on miRNAs in
Drosophila melanogaster
that function within systemic signaling pathways.
MicroRNAs (miRNAs) are short
