Extended Data Figure 1. Compositional analysis of Nsa1, Nog2 and Nmd3 particles.

a, Mostly non-overlapping assembly factors Nsa1, Nog2 and Nmd3 were used to purify sequential ribosome assembly intermediates. Proteins identified by mass spectrometry analysis were marked on the gel. Orange coloured proteins are only present in Nsa1-TAP particles, green coloured proteins are present both in Nsa1-TAP and in Nog2-TAP particles, light blue coloured proteins are present in all three purified particles to varying levels, dark blue coloured proteins are present only in Nog2-particles, pink coloured proteins are present both in Nog2- and Nmd3-particles in varying levels and yellow coloured proteins are present only in Nmd3-particles. TAP-tagged proteins are indicated by white asterisks. For gel source data, see Supplementary Fig. 1. b, The lifetimes of mostly non-overlapping ribosome assembly intermediates containing assembly factors Nsa1, Nog2 and Nmd3 are indicated. Assembly factors identified in each of Nsa1-TAP, Nog2-TAP and Nmd3-TAP associated samples were colour coded. The colour scheme is identical to that used in a. *Even though this protein was identified in all three intermediates, its levels decreased more than sevenfold from Nsa1-TAP particles to Nog2-TAP particles.