UNC-130/FOXD establishes, but does not maintain, a muscle gradient of UNC-129/TGF-β.
Expression of unc-130 and unc-129 are mutually exclusive in wild type muscle cells.
Low levels of UNC-130/FOXD are sufficient to prevent unc-129 expression in muscle.
Muscle activation of unc-130 depends on proper cell migration.
Multiple Forkhead factors act redundantly to fine-tune unc-129 and unc-130 expression.