ABSTRACT
Nearly 21-25-nt-long endogenous noncoding RNAs, commonly referred as microRNAs (miRNAs), regulate gene expression by partial sequences similarity to the complementary mRNA. miRNAs control a wide range of biological events during animal development, including developmental timing, cell proliferation, apoptosis, cellular differentiation, fine tuning (canalization) of gene expression, stem cell differentiation, etc. Two founding members of the miRNA family were initially identified in Caenorhabditis elegans as genes regulating developmental timing, and since then, hundreds of microRNAs have been identified in the majority of the metazoan genomes, including worms, flies, plants, and mammals. miRNAs have diverse
Overview ................................................................................................................ 123 8.1 Introduction ..................................................................................................124 8.2 Comprehensive Link between microRNA and Development ...................... 125 8.3 Biogenesis and Mechanism of Action of miRNAs ....................................... 128
8.3.1 Biogenesis of miRNAs ..................................................................... 128 8.3.2 Maturation of miRNAs ..................................................................... 128 8.3.3 Gene Regulation by miRNAs ........................................................... 130
8.4 miRNAs in Drosophila ................................................................................ 131 8.4.1 Drosophila miRNAs in Cell Death and Proliferation ...................... 131 8.4.2 Drosophila miRNAs in Developmental Processes .......................... 133 8.4.3 Drosophila miRNAs in Stem Cell Maintenance and
Proliferation ...................................................................................... 137 8.5 MicroRNA in Canalization and Genetic Buffering ..................................... 138
8.5.1 What Is Canalization? ....................................................................... 138 8.5.2 miRNA in Canalization of Fly Development ................................... 140
8.6 Future Challenges ......................................................................................... 142 8.7 Conclusions ................................................................................................... 142 Acknowledgments .................................................................................................. 143 References .............................................................................................................. 143
expression patterns and might regulate various developmental processes in fruit flies. The discovery of miRNA opens a new avenue in our understanding of complex regulatory developmental networks.
