The retroid family consists of genetic elements that encode proteins with the conserved motifs of retroviral reverse transcriptases (RT). Members of this family include a diversity of eukaryotic genetic elements such as viruses, transposable elements, organelle introns and plasmids, as well as the procaryotic retroposons.
In retroviruses, plant pararetroviruses, and retrotransposons containing long terminal repeat (LTR) (also called class I transposable elements or transposons), DNA synthesis is primed by specific transfer RNAs (tRNAs). All these retroelements contain a primer binding site presenting a Watson-Crick complementarity with the primer tRNA. In the retroviruses and plant pararetroviruses, the 3' end of the primer tRNA binds to the complementary binding site. In the case of retrotransposons, either the 3' end or the internal region of the primer tRNA is complementary to the primer binding site.
The most widely used primer tRNAs include tRNA Tryptophan (Trp), tRNA Proline (Pro), tRNA Lysine 1,2 (1,2Lys), tRNA Lysine 3 (3Lys), and tRNA Methionine (iMet). Other tRNAs such as tRNA Glutamine (Gln), tRNA Leucine (Leu), tRNA Serine (Ser), tRNA Asparagine (Asn) and tRNA Arginine (Arg) are occasionally used as primers.
Since artificial tRNAs do not possess the same biological properties as natural tRNAs, human purified tRNAs are more suitable for retroviral research, especially those related to HIV. Amerigo Scientific offers highly purified human tRNA extracted from a natural source such as the human placenta to meet the needs of retrovirus research.