This is a repeat domain involved in dimerisation of nuclear receptors proteins and in transcriptional regulation in general. It contains a Leu-Xaa-Xaa-Leu-Leu motif which has been characterized for the orphan nuclear receptor Dax-1, which represses the constitutively expressed protein Ad4BP/SF-1. The LXXLL motif plays in important role in binding of Dax-1 to Ad4BP/SF-1 [1]. The domain is subject to structure determination by the Joint Center of Structural Genomics.

1: LXXLL-related motifs in Dax-1 have target specificity for the orphan nuclear receptors Ad4BP/SF-1 and LRH-1. Suzuki T, Kasahara M, Yoshioka H, Morohashi K, Umesono K; Mol Cell Biol. 2003;23:238-49. PMID:12482977