1;1: Profiling the microRNAs;10 1.1;Introduction;10 1.2;The first miRNA profiling;11 1.3;miRNA profiling by multiplex real time PCR;12 1.4;In situ hybridization for miRNAs;15 1.4.1;Profiling by deep sequencing;16 1.5;References;16 2;2: The Wide Variety of miRNA Expression Profiles in the Developing and Mature CNS;18 2.1;Introduction;18 2.2;miRNAs can be widely expressed in proliferating and/or differentiated cells throughout the brain;19 2.3;miRNAs can show spatially restricted expression in the larval brain;20 2.4;Is miRNA expression conserved between larval and adult brain?;21 2.5;miRNAs of the same family or cluster can show subtle differences in brain expression;22 2.6;What do the miRNA expression profiles predict about the role of miRNAs in the brain?;23 2.7;Conclusion;24 2.8;References;24 3;3: Interactions between microRNAs and Transcription Factors in the Development and Function of the Nervous System;27 3.1;Introduction;27 3.2;MicroRNA-Transcription Factor Interactions at the Synapse;30 3.2.1;The mechanisms of microRNA/transcription factor interaction;30 3.2.2;Further identification of microRNA-transcription factor interactions;31 3.3;Concluding Remarks;32 3.4;References;33 4;4: A microRNA Feedback Circuit in Midbrain Dopamine Neurons;35 4.1;References;40 5;5: Fine-tuning mRNA Translation at Synapses with microRNAs;42 5.1;Introduction;42 5.2;Results;44 5.2.1;The prototypic dendritic microRNA: miR-134;44 5.2.2;The tip of the iceberg: miR-138 and beyond;45 5.2.3;Regulating the regulators: miRNAs under the control of neural activity;47 5.2.3.1;Activity-dependent transcription;47 5.2.3.2;Activity-dependent regulation of miRNA-associated complexes;48 5.2.4;Local vs. global: are miRNAs involved in synaptic homeostasis?;49 5.3;Concluding remarks;49 5.4;References;50 6;6: Neuronal P-bodies and Transport of microRNA-Repressed mRNAs;52 6.1;Introduction;52 6.1.1;MicroRNA: tiny molecules for huge challenges;53 6.1.2;Local translation and mRNA transport to synapses;53 6.2;P-bodies: properties and function in human cells;54 6.2.1;P-bodies are sites of storage for miRNA- repressed mRNAs;54 6.2.2;P-bodies are sites of degradation for aberrant mRNAs;55 6.3;P-bodies form a distinct class of dendritic granules;56 6.3.1;Neuronal P-bodies are present in dendrites and are involved in the miRNA pathway;56 6.3.2;dlP-bodies are transported along dendrites by motors;58 6.3.3;dlP-bodies become dynamic upon synaptic stimulation;59 6.4;Conclusion and perspectives;59 6.5;References;61 7;7: Crosstalk between microRNA and Epigenetic Regulation in Stem Cells;64 7.1;Introduction;64 7.2;Adult Neural Stem Cells and Neurogenesis;65 7.3;Epigenetic Regulation in Stem Cells;66 7.3.1;DNA methylation;66 7.3.2;MBD protein family;66 7.3.3;Mbd1 may regulate adult neural stem/progenitor cells;67 7.3.4;Histone modifications regulate adult NSCs and neurogenesis;68 7.4;MiRNA function in NSCs and Neurogenesis;68 7.5;Conclusion;72 7.6;References;72 8;8: microRNAs in CNS Development and Neurodegeneration: Insights from Drosophila Genetics;76 8.1;Introduction;76 8.2;microRNAs, the brain and disease;77 8.3;Approaches to the study of microRNA functions;79 8.4;microRNAs and neurodegenerative disease;80 8.5;A genome-wide screen for Drosophila microRNAs linked to normal CNS function and neurodegeneration;81 8.6;Prospects;81 8.7;References;82 9;9: Drosophila as a Model for Neurodegenerative Disease: Roles of RNA Pathways in Pathogenesis;85 9.1;Introduction;86 9.2;A role of microRNAs in polyglutamine toxicity;88 9.3;A pathogenic role for the CAG-repeat encoding mRNA in polyglutamine disease;91 9.4;Conclusions;94 9.5;References;94 10;10: microRNAs in Sporadic Alzheimer´s Disease and Related Dementias;97 10.1;Introduction;97 10.2;Gene dosage effects in neurodegenerative disorders: a role for miRNAs?;98 10.3;microRNAs in sporadic AD;99 10.4;Clinical relevance for miRNAs in neurodegenerative disease;102 10.5;Conclusion and Perspectives;102 10.6;References;102 11;11: microRNA Dysreg