To access the data, click or select the words “Appendix 1.” (A) BS are identifiable in WT samples as regions of weakened WGA staining where one fiber appears to bulge into its neighbor. (B) Most regions of 3-wk-old Ki samples had very few obvious BS. (C) Limited regions of 3-wk-old Ki samples had higher densities of BS-like structures. Arrowheads denote BS. Scale bar: 5 μm.