Figure 1
(a) Schematic review of DTC migration (based on Fancsalszky et al, 2014). DTCs are present on the distal ends of the gonad primordium in the L1 larval stage. In L1 and L2 larval stages the DTCs migrate along the ventral body muscles in response to attractive cues (first or ventral phase of migration). In the figure ventral body wall muscle is symbolized by a dashed line. In L3 stage distal tip cells turn towards the dorsal side (second or ventral to dorsal phase of migration), finally they turn again in L4 stage and migrate further proximally, in adulthood by reaching their final position opposite to the vulva (third or dorsal phase of migration). Developmental stages are indicated at the right of the figure. The different levels of NDK-1 influence DTC migration. (b) The precise dosage of ndk-1 is needed for the development of wild-type (N2) U-shaped gonad arms. Changes in the dosage of ndk-1 lead to different DTC migration phenotypes. (c) In ndk-1(+/−) heterozygotes we detected ectopically migrating DTCs (in this panel extra turn phenotype) with 24% of penetrance. (d) In ndk-1(−/−) homozygotes majority of the animals showed reduced migration, resulting in J-shaped gonad arms. (e) If we overexpressed NDK-1, incomplete migration was observed as well, however only in 14% of the cases due to mozaicism of the transgene. Scalebars are 100 μm, arrows show the position of the vulva, dotted lines follow the path of the DTCs, resulting the shape of the gonad.
