Viral TRAP RNAseq Data from Ipsilateral and Contralateral Corticospinal Neurons in Mouse

The spinal cord receives inputs from the cortex via corticospinal neurons (CSNs). While predominantly a contralateral projection, a less-investigated minority of its axons terminate in the ipsilateral spinal cord. We analyzed the spatial and molecular properties of these ipsilateral axons and their post-synaptic targets in mice and found they project primarily to the ventral horn, including directly to motor neurons. Barcode-based reconstruction of the ipsilateral axons revealed a class of primarily bilaterally-projecting CSNs with a distinct cortical distribution. The molecular properties of these ipsilaterally-projecting CSNs (IP-CSNs) are strikingly similar to the previously described molecular signature of embryonic-like regenerating CSNs. Finally, we show that IP-CSNs are spontaneously regenerative after spinal cord injury. The discovery of a class of spontaneously regenerative CSNs may prove valuable to the study of spinal cord injury. Additionally, this work suggests that the retention of juvenile-like characteristics may be a widespread phenomenon in adult nervous systems. This TRAP sequencing data was used to determine the molecular similarity to regenerating and embryonic CSNs. To determine the molecular characteristics of ipsilateral and contralateral CSNs, we used retrograde viral TRAP in CSNs and sequenced both input mRNA and TRAP immunoprecipitated RNA from 5 paired biological replicates of three animals each