Cep120 is required for centriole duplication. (A) Cep120 depletion from MEF cells by lentiviral expression of shRNAs. Lysates were probed for Cep120 and α-tubulin. Numbers in parentheses indicate molecular mass in kilodaltons. (B) Loss of Cep120 in MEFs infected with lentivirus expressing control or Cep120 shRNA and GFP to identify infected cells (outlined in white). Bar, 10 µM. (C) Centriole duplication in S phase–arrested MEFs after treatment with the indicated shRNAs. Results shown are the mean of three independent experiments (n = 600 for each sample). (D) Representative images showing reduction of centriole number at spindle poles of mitotic MEFs depleted of Cep120. Insets are magnified images of the centrosome region. (E) Quantification of centriole number over time in control and Cep120-depleted MEFs; centrioles were counted beginning on day 7 after infection. n = 400 for each time point. (F) The loss-of-centriole phenotype in Cep120-depleted human RPE-1 cells is rescued by expression of mouse Cep120. n = 400 for each time point. (G) Sas-6 recruitment to centrioles is unaffected by loss of Cep120. S phase–arrested MEFs were stained for Cep120 (green) and Sas-6 (red). n = 200 for each sample. (E–G) Results shown are a mean of two independent experiments. Data are means ± SD. Bar, 0.5 µm.