Porcine Endogenous Retrovirus (PERV-MSL) is a simple retrovirus isolated from lymphocytes of miniature swine. Constitutive production of PERV-MSL RNAs has been detected in normal leukocytes and in multiple organs of swine. The copy numbers of full-length PERV sequences per genome (approximately 8 to 15) vary among swine strains (Akiyoshi et al. 1998). Phylogenetically, PERV-MSL belongs to the genus Gammaretrovirus and is morphologically consistent with mammalian C-type retroviruses. The genomic structure of PERV-MSL is 8.13 Kb size including LTRs of 564 and 458 nt. The internal region of this retrovirus displays a Primer Binding Site (PBS) complementary to a tRNAPro, Open Reading Frames (ORFs) for the gag, pol and env genes characteristic of retroviruses, and a Polypurine Tract (PPT) adjacent to the 3´LTR (Akiyoshi et al. 1998).
Figure not to scale. If present, long terminal repeats (LTRs) have been highlighted in blue. Amino acid motifs noted with lines indicate the conserved residues in each protein domain, abbreviations below mean:
||DU or DUT=dUTPase
||TAV or IBMP=transactivator/viroplasmin or inclusion body matrix protein
||PBS=primer binding site
||ATF=aphid transmission factor
||VAP=virion associated protein