Fig. 1

Identification of the H3 and H3.3 interactomes in Tetrahymena. A Top, Neighbor-joining phylogenetic analysis of RD and RI H3 proteins. Different species are highlighted in different colors. The numbers on the branches represent confidence values based on 1000 bootstrap replicates. Red stars indicate ciliates. Accession numbers are shown in brackets. Silhouettes adapted from http://phylopic.org/. Bottom, Western blotting analysis using whole cell lysates prepared from vegetative Tetrahymena cells expressing H3-GFP (H3 ∼ 15.43 kDa + GFP ∼ 27 kDa) and H3.3-FZZ (H3.3 ∼ 15.5 kDa + FZZ ∼ 18 kDa). The blots were probed with the indicated antibodies. B Left, Schematic representation of tandem affinity purification procedure. Right, Network representation of high-confidence (FDR ≤ 0.01) H3, H3.3, and H4 co-purifying proteins. See Additional file 1: Tables S1, S2 for complete AP-MS results. C Comparative domain analysis of Tetrahymena Nrp1 protein against Homo sapiens, Xenopus laevis, and Saccharomyces cerevisiae orthologs. Overall sequence identity among the orthologs is shown on the right. D Western blotting analysis using whole cell lysates prepared from growing Tetrahymena cells expressing Nrp1-FZZ (Nrp1∼ 59 kDa + FZZ ∼ 18 kDa). The blot was probed with the indicated antibodies. E Dot plot representation of high-confidence (FDR ≤ 0.01) Nrp1 and Asf1^Tt co-purifying proteins from vegetatively growing Tetrahymena. Inner circle color shows the average spectral count, the circle size indicates the relative prey abundance, and the circle outer edge is the SAINT FDR. See Additional file 1: Table S3 for complete AP-MS results for Nrp1. F Indirect immunofluorescence analysis of Nrp1-GFP in growing Tetrahymena. Nrp1 localization at different cell cycle stages is also indicated in the left panel. Untagged wildtype cells were used as a control. DAPI stained the nuclei, and the position of the MAC and MIC is indicated with arrows and arrowheads, respectively