Extended Data Fig. 1: Co-expression of core complex subunits, size exclusion chromatography and glycerol gradient sedimentation analyses of the core complex.

a, Silver-stained SDS-PAGE gels (top) and anti-Flag western blot (WB; center) of Spo11 complexes after purification on nickel resin. Absence of Rec102, Rec104, or Ski8 leads to poor solubility of Spo11. Bottom: anti-Flag western blot of lysed Sf9 cells showing Spo11 expression levels. Asterisks: C-terminal truncation of Spo11 that retains the affinity tag and interaction with Ski8. b, Size exclusion chromatography of purified core complex with and without MBP tag on Rec102. Silver-stained SDS-PAGE gels of eluted fractions are shown above, with chromatograms from absorption at 280 nm below. c, Glycerol gradient sedimentation of MBP-tagged Spo11 core complexes. The silver-stained SDS-PAGE gel shows fractions collected from the bottom of the gradient. Quantification of protein signal from two independent experiments is shown together with molecular weight markers run on a separate gradient and quantified by Bradford assay. Note: Material in the void volume (panel b) and at the bottom of the glycerol gradient (panel c) lacks Ski8, which is consistent with Ski8 being required for solubility.