Fig. 2. The M lineage phenotypes of cc609 mutants. All images are ventral/lateral views with anterior to the left. (A-H) Wild-type (A,B,E,F) and cc609 mutant (C,D,G,H) animals at the late L2 stage (A-D) and adult stage (E-H). SMs are visualized using hlh-8::gfp and labeled with red arrows. CCs are visualized using intrinsic CC::gfp; embryonic CCs are labeled with white arrowheads and M-derived CCs with blue arrows. Type I vulval muscles are visualized using egl-15::gfp and labeled with green arrows. Note the presence of two SMs in the wild-type larva (A,B) and four SM-like cells in the cc609 larva (C,D). B and D show the SM-like cells at higher magnification. Also note the lack of M-derived CCs in cc609 larva (C,G) compared with wild-type animals (A,E). cc609 adults have extra type I vulval muscles (vm1-like cells) (G,H) compared with wild type (E,F). F and H show the vulval muscles in higher magnification. (I-L) Representations of the hermaphrodite M lineage in wild-type (I) and different cc609 mutant (J-L) animals. Unmarked cells refer to BWMs. (I) Wild-type animals always give rise to two CCs, two SMs and 14 BWMs. (J-L) cc609 mutant animals consistently have a loss of M-derived CCs and some BWMs, with the concomitant gain of SM-like cells.