Topic Overview:

The mammalian neocortex, the region of the brain responsible for cognitive function, sensory perception, and consciousness, is a complex, highly organized structure that contains hundreds of different neuronal cell types and a diverse range of glia. There are two broad classes of cortical neurons: interneurons, which make local connections, and projection neurons, which extend axons to distant intracortical, subcortical, and subcerebral targets. To investigate the mechanisms underlying the generation of neuronal diversity in the neocortex, Molyneaux and colleagues purified individual populations of cortical projection neurons from the earliest stages of development and analyzed the dynamics of their transcriptome.

Molyneaux used combinations of antibodies to subtype specific transcription factors to purify three different projection neuron populations—corticospinal, corticothalamic, and interhemispheric callosal. He has identified large programs of cell-type specific coding and long noncoding RNAs that might play critical roles in regulating transcription during development. He has also identified novel splice isoforms and subtype-specific promoter usage.  Together, these data provide new insights into the transcriptional landscape in developing projection neurons.