Transcription factor Sp9 is a negative regulator of D1-type MSN development [scRNA-Seq]

The striatum is the main input structure of the basal ganglia, receiving information from the cortex and the thalamus and consisting of D1- and D2- medium spiny neurons (MSNs). D1-MSNs and D2-MSNs are essential for motor control and cognitive behaviors and have implications in Parkinson’s Disease. In the present study, we demonstrated that Sp9 positive progenitors produced both D1-MSNs and D2-MSNs and that Sp9 expression was rapidly downregulated in postmitotic D1-MSNs. Furthermore, we found that sustained Sp9 expression in lateral ganglionic eminence (LGE) progenitor cells and their descendants led to promoting D2-MSNs identity and repressing D1-MSNs identity during striatal development. As a result, sustained Sp9 expression resulted in an imbalance between D1-MSNs and D2-MSNs in the mouse striatum. In addition, the fate-changed D2 like-MSNs survived normally in adulthood. Taken together, our finding supported that Sp9 was sufficient to promote D2-MSNs identity and repress D1-MSNs identity, and Sp9 was a negative regulator of D1-MSNs fate. Single-cell RNA sequencing was performed using 10X Genomics Chromium technology V3 on E14.5 LGE (8 total samples)