Tnt1 was the first Ty1/Copia transposable element found in Nicotiana tabacum (Grandbastien et al. 1989). Tnt-1 belongs to the Tork clade within Branch 2 of the Ty1/Copia family (Llorens et al. 2009). Its genome is 5334 bp in size and includes two 610-bp LTRs flanking an internal region that contains a Primer Binding Site (PBS), a single Open Reading Frame (ORF) of 1328 amino acids and a final Polypurine Tract (PPT) (Grandbastien et al. 1989). The ORF shows the typical gag and pol protein domains of Ty1/Copia LTR retrotransposons: gag, protease, integrase, reverse transcriptase and ribonuclease H.
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