Figure 4
From: Homologues of bacterial TnpB_IS605 are widespread in diverse eukaryotic transposable elements
CRe-1, 2, 3 elements. (A) CRe-1, 2, 3 consensus sequences and the exons (black boxes). Dotted areas indicate the 5′-ends, approximately 200- bp long, which are 98% identical to those of confirmed Helitrons. Asterisks at the 3′-ends indicate the short homologous regions in CRe-1, 2, 3 and Helitron elements (C, D). The corresponding sequences of the15 example loci (1 to 15) are indicated by solid lines below. Dashed lines mark the internal deletion regions. Nine of them are flanked by target site duplications (TSDs) indicated by small diamonds. Note that locus 1 and 7 include short segments of ‘non-Fanzor’ sequences (gray line) at the 5′-ends. The sequences of the 15 loci are shown in Additional file 8B. (B) Examples of the nine TSD sequences (shaded). Note that the 5′-TSDs are immediately downstream of TTTT tetra-nucleotides. (C) Helitron-1 _CRe and non-autonomous Helitrons. (D) The alignment of the 3′-ends of Helitrons and CRe-1,2,3. The 3′ asymmetrical terminal inverted repeats (ATIRs) are boxed. (E) Target specificity of Helitron-1N1 _CRe elements. They insert specifically between TTTT and T/C and produce no TSDs. Helitron-1N2 _CRe elements also insert after TTTT. Three examples of the pre- and post-insertion sites are shown. (F) The illustration of the 5′-truncation or 3′-overabundance in CRe-1 elements: graphical summary of a NCBI online BLASTN search of the Chlamydomonas reinhardtii genome with the consensus of CRe-1.