William G. Hirst, Abin Biswas, Kishore K. Mahalingan, Simone Reber

To show that indeed intrinsic tubulin properties contribute to setting spindle length, the classic experiment would be a depletion/add-back experiment, i.e., deplete tubulin from the extract of one Xenopus species and add back tubulin from the other species. Therefore, we tried to deplete endogenous tubulin from X. laevis egg extracts, add back X. tropicalis tubulin, and assemble spindles. However, we and others (Heald lab and Good lab, personal communication) did not succeed in significantly depleting tubulin from extracts. Although we successfully pulled down tubulin (Figure S4A), we were not able to significantly reduce the extract tubulin concentration (Figure S4B). Therefore, we decided to perform the depletion and add-back experiment in silico using the cytoskeletal simulation software Cytosim (http://www.cytosim.org) [

  • Loughlin R.
  • Wilbur J.D.
  • McNally F.J.
  • Nédélec F.J.
  • Heald R.
Katanin contributes to interspecies spindle length scaling in Xenopus.