The suppression of L1 activity may alter the expression of depression-related genes, such as those coding for dopamine receptor 3 (DRD3) and neurotransmitter transporters (SLC6A5, SLC6A6 and SLC6A9); L1 may also reshape the genetic circuitry in the neurobiological processes30, 54. Here, SLC6A9 is linked to depressive disorder.