Figure 8

Possible transcription-associated recombination mechanism. A possible transcription-associated recombination mechanism is proposed for spreading of telo boxes, microsatellites and Y patches within plant genomes. (A) open transcription pre-initiation complex and R-loop at promoter-proximal pausing sites; (B) generation of free 3'OH recombinogenic ssDNA by endonucleases; (C) the free 3'OH ends are substrates for telomerase or terminal transferase; (D) 3' end invasion at homologous open sites followed by error-prone DNA repair; (E) acquisition of a telomere repeat unit or new nucleotides. See text for comments. TSS: transcription start site. TdT: terminal transferase.