The invention provides novel TRIM polypeptides, proteins, and nucleic acid molecules. In addition to isolated, full-length TRIM proteins, the invention further provides isolated TRIM fusion proteins, antigenic peptides and anti-TRIM antibodies. The invention also provides TRIM nucleic acid molecules, recombinant expression vectors containing a nucleic acid molecule of the invention, host cells into which the expression vectors have been introduced and non-human transgenic animals in which an TRIM gene has been introduced or disrupted. The present invention also provides methods and compositions for the diagnosis and treatment of viral infection and/or replication, e.g., HIV infection. The invention further provides methods for identifying a compound capable of treating or preventing viral infection and/or replication, e.g., HIV infection and AIDS. In addition, the invention provides a method for treating a subject having a viral infection and/or replication, e.g., HIV infection using the modulators of the invention.