The target specificity of the LXXLL related motifs was indicated by the observations that Ad4BP / SF 1 , ERalpha ( NR3A1 ) , LRH 1 , ERR 2 ( NR3B2 ) , and fly FTZ F 1 ( NR5A3 ) interacted through their ligand binding domains with all the LXXLL related motifs in Dax 1 whereas HNF 4 ( NR2A1 ) and RORalpha ( NR1F1 ) did not . ^^^