Fig. 7. Suppression of rnt-1 cell division failures by silencing of cki-1. (A) Graph showing the number of seam cells present in adult hermaphrodites (assayed by scm::GFP expression) in wild-type (n=30), rnt-1(ok351) (n=32), cki-1(RNAi) (n=36) and rnt-1(ok351); cki-1(RNAi) (n=31) animals. All strains were in a him-5(e1490) background. cki-1 RNAi causes an increase in seam cell number relative to wild type (P<0.0001). The number of seam cells in rnt-1(ok351); cki-1(RNAi) animals is restored to near wild-type levels (no significant difference compared with wild type, P>0.05). Error bars represent the standard error of the mean. (B) cki-1::GFP expression in the seam cells of L1 larvae. The left hand panel shows the L1 stem cell division pattern of V1-V6 in wild-type and rnt-1(ok351) animals. Seam cells are indicated by circles, hyp7 nuclei by squares. Crosses in the lineage diagrams indicate where divisions failed. (i,ii) Worms hatched in the absence of food, kept 24 hours at 20°C then re-fed and the division pattern examined by observing hypodermal and seam nuclei present in late L1 or mid L2 stages. In this situation, the L1 stem cell division failed in rnt-1 mutants 52% of the time (n=84). In wild type, the division pattern was always normal (n=66). (iii,iv) Worms were examined in late L1 after hatching on food, having never been subjected to starvation. Wild-type animals always underwent the normal L1 division (n=60) and rnt-1(ok351) animals displayed the normal division pattern 98% of the time (n=60). The right-hand panel shows cki-1::GFP expression under these conditions, prior to the time of the expected L1 stem-cell division. Individual seam cells are labelled. The increased cki-1::GFP expression observed in rnt-1 L1 larvae hatched in the absence of food, compared with wild-type animals subjected to the same treatment, was consistently observed (n=30). Scale bars: 20 µm.