The Leid laboratory is primarily focused on the in vivo role of the transcriptional regulatory protein known as Ctip2/Bcl11b. The laboratory discovered the protein and cloned the corresponding cDNA in 2000. The Leid group subsequently defined the molecular and cellular basis for the activity of this transcription factor, and demonstrated that the protein plays key roles in the development of several organ systems. The latter studies were conducted using a mouse that was conditionally null for Ctip2/Bcl11b expression, which was created in collaboration with the group of Daniel Metzger (IGBMC, Illkirch, France).