Domain architecture of histone chaperones from Arabidopsis and rice. Diagram shows scaled representation of the primary structure of histone chaperones belonging to (A) NAP, (B) CAF1 (CAF1A, CAF1B, and CAF1C), (C) FACT (SPT16 and SSRP), (D) NASP, (E) ASF1, (F) HIRA, (G) SPT6 families from Arabidopsis and rice. Positions of various domains along the respective protein sequences have been shown by different shapes as depicted in the key at the right. It is to be noted that each family, except CAF1B, possesses one or more characteristic domains while some families possess domains found in other families of histone chaperones as well. Refer text for the Pfam ids of the domains.