Analysis of the TLX–Atrophin interaction. (A) Atrophin contact residues are conserved in dTLX, rfbTLX, and hTLX, which define an autorepressed pocket. (B) TLX contact residues are conserved in dAtrophin (NP_996025), rfbAtrophin (XP_008194914), Atrophin-1 (NP_031907), and Atrophin-2 (NP_001078961), which define an ALXXLXXY motif (Atro motif; highlighted in gray) in the Atro box sequence. (C) Mutations in the dTLX autorepressed pocket affected its interactions with Atrophin-1 and Atrophin-2 in mammalian two-hybrid assays. (D) Mutations in the hTLX autorepressed pocket compromised its interactions with Atrophin-1 and Atrophin-2 in mammalian two-hybrid assays. (E) Mutations in the Atro motif of Atrophin-1 reduced its interactions with dTLX and hTLX in mammalian two-hybrid assays. (F) Mutations in the Atro motif of Atrophin-2 reduced its interactions with dTLX and hTLX in mammalian two-hybrid assays. All error bars indicate SD (n = 3). All experiments were repeated at least twice.