Cooperates with ASF1A to promote replication-independent chromatin assembly (By similarity). May regulate the transcription of a variety of genes controlling cell growth. Interacts with ASF1, HDAC1, HDAC2 and RBBP4. Expressed from gastrulation onwards with predominant expression in the neuroepithelium during neurulation. Expressed in regions of the embryo containing migrating neural crest cells, particularly those emanating from rhombomeres 4 and 6. Expressed throughout the rostral mesenchyme with higher levels of expression in regions containing neural crest cells. At later stages strong expression is seen in the neural crest derived regions of the head, the branchial arches and the pharyngeal pouches. Expression at the rhombomere boundaries increases around stage 16. Belongs to the WD repeat HIR1 family.