The width of the central band of AChR clusters in diaphragms at E14.5 is narrower in agrn^−/− (A) than in control (A′) littermates. A difference is also found between Hb9^−/− mutants (B) and control (B′) littermates. C, Widths of AChR cluster bands (means ± SE) in agrn^−/− and Hb9^−/− mutants relative to control littermates. Data are based on five agrn^−/− mutants (2 litters; p < 0.05) and four Hb9^−/− mutants (3 litters; p < 0.1). For method, see supplemental Figure 2 (available at www.jneurosci.org as supplemental material). Scale bar, 70 μm.