mmpa and β1-integrin are essential for migration and cell extension formation. (A-L) WFISH shows migration of NBs (green) and early progeny (magenta) at 7 dpa in control gfp(RNAi) (A-C,G-I) and lack of migration in mmpa(RNAi) (D-F) and β1-integrin(RNAi) (J-L) animals. Insets show the presence of NBs and early progeny with extended cytoplasmic projections in the migratory region of gfp(RNAi) worms (B,C,H,I, arrowheads) that are almost absent in mmpa(RNAi) (E,F) and β1-integrin(RNAi) (K,L) worms (n=5). Brackets indicate the shielded area. (M) Distance migrated by NBs (green) and early progeny (magenta) at 7 dpa in mmpa(RNAi) and β1-integrin(RNAi) animals compared with control gfp(RNAi) worms (n=5). Each dot represents the average distance migrated by the ten most distal cells from each animal. Mean±s.d. Student's t-test, *P<0.05. (N) Quantification of NBs (green) and early progeny (magenta) with extended processes in mmpa(RNAi), β1-integrin(RNAi) and control gfp(RNAi) animals at 7 dpa (n=5). Mean±s.d. Student's t-test, *P<0.05. See also Fig. S3.