Fig. 1. Preferential localization of APC and EB1 to a subset of centrioles. (A) Schematic representation of centrosome duplication during the cell cycle and localization of centrosome marker proteins. Pericentrin and -tubulin localize to the pericentriolar material (lilac area); centrin localizes to the centrioles (light blue tubes). MT-anchoring appendages on the mother centriole are marked in black. (B) Basal section of a MDCK cell co-stained for APC (red) and -tubulin (green). Arrowheads mark cortical APC clusters, arrow marks localization of APC with -tubulin. Bar, 10 µm. Insets show another example of the centrosome region of an MDCK cell at higher magnification. Bar, 2 µm. (C) Sections of U-2 OS cells showing the centrosome regions of cells immunostained for -tubulin (green in a-c), pericentrin (red in g-j) and centrin (green in d-f,k-m) and co-stained for APC (red in a-f) and EB1 (green in g-m). Cells with two centrosomes marked by pericentriolar pericentrin (red in g-j) or -tubulin (green in a-c) or with four centrioles marked by centrin (green in d-f,k-m) are also shown. APC and EB1 localize preferentially to one of two centrosomes (a-c for APC, g-j for EB1) and to two of four centrioles (d-f for APC) or to one of four centrioles (k-m for EB1). See also Movie 1 (http://jcs.biologists.org/supplemental). Bar, 2 µm.