The heterotrimeric Elba complex is required for chromatin domain boundary function during early embryogenesis. It binds to a 8-bp sequence 5'-CCAATAAG-3' in the Fab-7 insulator or boundary element in the bithorax complex and contributes to its insulator or boundary activity (PubMed:23240086). Elba1 may act as a transcriptional repressor and binds the palindromic sequence 5'-CCAATTGG-3' to mediate transcriptional repression (PubMed:25561495). The heterotrimeric Elba complex consists of Bsg25A/Elba1, Elba2 and Elba3. Expression is developmentally restricted, peaks at the blastoderm stage (2-4 hours) and then disappears (at protein level). The BEN domain mediates DNA-binding.