Truncation of Lk ARSs to narrow down essential functional regions. (A-C) Sub-fragments of three Lk ARSs (two more shown in Additional File 2, Figure S1) were cloned and tested for ARS function. Black boxes represent functional fragments. Red boxes represent non-functional fragments. For each ARS, the position of the best match to the 9 bp Lk ACS is indicated by a blue box. The extent of the truncation in basepairs is indicated on the left of the graphics (L = truncated from the left, R = truncated from the right). The length of the original full-length fragment isolated from the screen is indicated next to the first fragment from the top. *: This fragment retains very weak ARS activity.