Fig. 2.

slit interacts genetically with integrin mutations. Embryos mutant for β-integrin (A,mys), αPS1 integrin (B,mew), αPS2 integrin (C,if), and αPS3 integrin (D,scab) have a range of axon guidance phenotypes; more severe examples are represented here. Midline errors (arrowheads) can be found in all integrin mutants; however, they occur more frequently and involve more axons inscab and progressively fewer in if,mys, and mew mutant embryos. Axon guidance errors are seen in embryos heterozygous for both an integrin gene and slit (E, mys;F,mew; G,if; and H, scb) and in embryos homozygous mutant for an integrin gene and also heterozygous for slit (I, mys;J, mew; and K,if). Midline axon crossover is most frequent inscb/sli heterozygotes and then less often inif, mys, and mew double heterozygotes, respectively.