Figure 1. Schematic representation of the major features of ERV-Fc proviruses.
The region colored in blue indicates gag, brown indicates pol, and yellow represents env coding regions. The gray-colored regions indicate the two long terminal repeat (LTR) regions. Vertical lines within these regions indicate where proteolytic cleavage would occur between protein subunits. The identity of these subunits is indicated below the schematic: MA = matrix, CA = capsid, NC = nucleocapsid, PR = protease, RT = reverse transcriptase, IN = integrase, SU = surface, TM = transmembrane, PPT = polypurine tract. The probable location of the viral RNA packaging motif is indicated by ψ. At the termini of the retroviral LTR sequences is shown the canonical TG/CA dinucleotides as well as the 5 nucleotide target site duplications (TSDs) flanking the provirus. ERV, endogenous retrovirus.