Biparous: a novel bHLH gene expressed in neuronal and glial precursors in Drosophila.

Genetic studies have uncovered many genes that are involved in the first steps of neuronal development in Drosophila. Less is known about the intermediate steps during which individual precursor cells follow either the neuronal pathway or the glial pathway. We report the identification of a novel bHLH gene, biparous, expressed in neuronal and glial precursors in Drosophila. Unlike most bHLH genes, biparous expression continues to the final stages of neurogenesis in the embryo. Expression of biparous is not observed in end stage postmitotic neurons and precedes the expression of repo, a gene activated in later stages of glial differentiation. The bHLH domain is sufficiently different from previously described bHLH domains to imply a novel function.