The invention provides methods and compositions relating to the Tax-response Complex-1 (TRC-1) a transcription complex associated with disease, particularly HTLV infection. TRC-1 is composed of novel forms of JunB and a member of a novel protein family called small nuclear factors or SNFs. The expression of these compounds are shown to correlate with cell lineage, activation and infection. SNFs and T-cell specific forms of JunB, find particular use in screening assays for agents or lead compounds for agents useful in the diagnosis, prognosis or treatment of disease, particularly HTLV infection. Nucleic acids encoding SNFs, and SNF-specific binding agents find use in diagnosis and as commercial reagents for the biopharmaceutical industry.