Simian Immunodeficiency Retrovirus of Macaques (SIVMAC) is a lentivirus closely related to HIV-2 in both genomic structure and sequence. SIVMAC has cytophatic effects and tropism towards CD-4 lymphocytes, and induces acquired Immunodeficiency Syndrome -AIDS- (Chakrabarti et al. 1987). The genomic structure of SIVMAC is 9.6 Kb in size including LTRs of 1 Kb (pro-5´LTR R/U5 and pro-3´LTR 3′ U3/R of 318 nt and 689 nt, respectively. The internal region of this retrovirus displays a Primer Binding Site (PBS) complementary to a tRNALys3; Open Reading Frames (ORFs) for gag, pol and env genes characteristic of retroviruses, tat and rev (both expanded in two exons) and vif (orf-q), which are three accessory genes common in other lentiviruses, vpx (orf-x), vpr (orf-r), and nef (ORF-F) accessory genes specifical of primate lentiviruses, and a Polypurine Tract (PPT) adjacent to the 3'-LTR (Chakrabarti et al. 1987).
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