May participate in DNA packaging/capsid maturation events. Promotes efficient incorporation of tegument proteins UL46, UL49, and US3 homologs into virions. May also play a role in capsid transport to the trans-Golgi network (TGN) (By similarity). MDFKYSDTVIHNGVVFYITDGGHRVYFLYGGCLLSVPRPHATAESGEIAKFGLTLRGLTHNDRVVANYVRSELNRTGRHESAPSSEEDVFVDRLEVLAQGAQAFGRDICGSFDLEVYDPYLAECMVSLKVTSGLIVSTGRDIPQDGMLHLYTVPTITNASSGFIYTPNIACFTLVQAYLTELPPELETLISGLFDHIPVARPPLRDESGGHSRTDIIVTSPRAVKTMAIGGTTRCSKRPLRKTVVSDFVQVRLIPKPCSIWDSASRVASGASLQSLQLLFKIADEIILIEEPWPGLDEHLNQARSTIVDAILAVYGNEGKLRFFGGKLTQQGVTTLQRFVLCQFILGKWNLINCYAALEQLAESYIGAVPEARDPLPDPHLVADAVNEIIRESGILGELCEIIVRYTQPTDPVNGSGSEVVELEARLLAEFAANATRVELGLSSYDEVRNMEARIASVLNKLYAKDGIGGAAQVACRILGSGLPVAIVLNVSSITAFDGLDLSRKGAYYLYYLLSERLKRGGVTVHVSRK 40 530 40 Tegument protein UL21 homolog TG21_EHV1V