Fig. 7.

Model for LC migration in C. elegans. (A) LC migration consists of two levels of regulation: a basal migration program and stage-specific modifiers such as nhr-67. The basic shape of the gonad during the L1 through L4 stages is indicated in black. The basal migration program (dark blue) is implemented at the start of LC migration in the L1-to-L2 molt and continues until LC death. The genes expressed throughout LC migration and used in the basal program include lag-2, mig-2, gon-1 and him-4. nhr-67 regulates changes in LC migration from the early L3 stage through to the mid/late L4 stage (red). There are likely to be other stage-specific regulators (purple and light blue) because LC development up until the L3 stage and in the late L4 stage occurs normally in nhr-67-deficient males. In the absence of nhr-67-dependent migration, the basal migration program continues and the LC migrates but remains in its early L3 stage form for an extended time. (B) nhr-67-dependent migration can be dissected into specific components. nhr-67 negatively regulates unc-5, but positively regulates zmp-1 expression, polarization of LC shape and migration speed.