Coiled Coil Domain Containing Protein 85B (CCDC85B)

HDAg and DIPA interact in mammalian cells through the coiled-coil motifs of each partner.Overexpression of DIPA inhibited HDV replication, whereas overexpression of HDAg reversed the inhibition, suggesting that HDAg may assist HDV replication by forming a complex with DIPA.

Northern blot analysis revealed expression of a 1.1-kb transcript in a human hepatic cell line that is present in most human tissues, including the liver. Sequence analysis predicted that the 202-amino acid protein is 24% identical and 56% similar to the similarly-sized HDAg with which it shares a distinctive proline- and glycine-rich C terminus, 2 leucine heptad repeats with the potential to form coiled-coil protein-interaction domains, and 1 of 2 arginine-rich motifs implicated in RNA binding.