Fig 2: SLI frequency is increased in old Fa2h-/- mice. A Phalloidin staining of teased fibers from 17-month-old Fa2h+/+ and Fa2h-/- mice. B Quantification of SLI frequencies in teased fibers of sciatic nerves from 4-month-old (n = 5 mice per genotype; N = 50 fibers analyzed) and 17-month-old mice (n = 7 mice per genotype; N = 70 fibers). The number of SLIs was significantly increased in old but not young Fa2h-/- mice. p value in bold indicates significant difference (t-test). C The average internodal diameter of axons examined to determine the SLI frequencies was not significantly different between genotypes. All data are shown as mean ± SD (n = 5–7) of the average SLI frequency or internodal diameter per mouse. D Immunofluorescence staining of Cadm4 and Lin7 in teased fibers from 17-month-old Fa2h+/+ and Fa2h-/- mice. Both proteins co-localized and showed a similar distribution (mainly present in SLIs) in both genotypes