MicroRNAs show a wide diversity of expression profiles in the developing and mature central nervous system

Marika Kapsimali^*¹^,2^,3 , Wigard P Kloosterman^*⁴ , Ewart de Bruijn⁴ , Frederic Rosa⁵ , Ronald HA Plasterk⁴ and Stephen W Wilson¹

¹Department of Anatomy and Developmental Biology, UCL, Gower Street, London WC1E 6BT, UK

²DEPSN, UPR2197, CNRS, avenue de la Terrasse, 91198, Gif-sur-Yvette, France

³Génétique Moléculaire du Développement, INSERM U784, Ecole Normale Supérieure, 46, rue d'Ulm, 75230 Paris, France

⁴Hubrecht Laboratory, Centre for Biomedical Genetics, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands

⁵Génétique Moléculaire du Développement, INSERM U784, Ecole Normale Supérieure, 46, rue d'Ulm, 75230 Paris, France

author email corresponding author email* Contributed equally

Genome Biology 2007, 8:R173doi:10.1186/gb-2007-8-8-r173


Published:	21 August 2007

Subject areas: Molecular biology, Development, Genetics

Abstract

Background

MicroRNA (miRNA) encoding genes are abundant in vertebrate genomes but very few have been studied in any detail. Bioinformatic tools allow prediction of miRNA targets and this information coupled with knowledge of miRNA expression profiles facilitates formulation of hypotheses of miRNA function. Although the central nervous system (CNS) is a prominent site of miRNA expression, virtually nothing is known about the spatial and temporal expression profiles of miRNAs in the brain. To provide an overview of the breadth of miRNA expression in the CNS, we performed a comprehensive analysis of the neuroanatomical expression profiles of 38 abundant conserved miRNAs in developing and adult zebrafish brain.

Results

Our results show miRNAs have a wide variety of different expression profiles in neural cells, including: expression in neuronal precursors and stem cells (for example, miR-92b); expression associated with transition from proliferation to differentiation (for example, miR-124); constitutive expression in mature neurons (miR-124 again); expression in both proliferative cells and their differentiated progeny (for example, miR-9); regionally restricted expression (for example, miR-222 in telencephalon); and cell-type specific expression (for example, miR-218a in motor neurons).

Conclusion

The data we present facilitate prediction of likely modes of miRNA function in the CNS and many miRNA expression profiles are consistent with the mutual exclusion mode of function in which there is spatial or temporal exclusion of miRNAs and their targets. However, some miRNAs, such as those with cell-type specific expression, are more likely to be co-expressed with their targets. Our data provide an important resource for future functional studies of miRNAs in the CNS.