microRNA function in neurogenesis

In the October15th issue of G&D, Dr. Fen-Biao Gao and colleagues at UCSF report that microRNA-9a (mir-9a) regulates neural development in the fruit fly, Drosophila. Using loss-of-function analysis, Dr. Gao and colleagues demonstrate that mir-9a is required for the precise production of sensory organ precursor cells in the Drosophila peripheral nervous system (PNS). mir-9a-mutant embryos form additional PNS neurons, and mutant adults wings display extra sensory bristles. The researchers show that mir-9a post-transcriptionally represses the transcription factor, Senseless, to regulate the precise number of neuronal precursor cells in Drosophila embryos and adults. "miR-9a is 100% conserved from flies to humans at the nucleotide sequence level and is highly expressed in fetal brains, suggesting that a similar mechanism may operate in mammalian neurogenesis as well," explains Dr. Gao.