Fig. 7.

Loss of Blimp1 alters lumen formation and maturation in MEC 3D cultures. (A) Wild-type and Prdm1^CA/CA:ROSA26:CreERT2 (Blimp1^cKO) day 6 4OHT-treated MEC 3D acini stained for GM130 (green) and Par3 (red; top panel) or podocalyxin (Podxl, red; bottom panel). MECs were treated with 4OHT for 24 h following plating. Scale bars: 50 μm. (B) Percentage of acini with ribbon-like and fragmented localization of GM130 Golgi in wild-type and Blimp1^cKO day 6 4OHT-treated MEC 3D acini (wild type: n=30 acini; Blimp1^cKO: n=30 acini). (C) Deviation of the Golgi from acini centre (α°) (wild type: n=30 acini; Blimp1^cKO: n=30 acini). (D) Percentage of acini with Golgi uncoupled to centre (wild type: n=30 acini; Blimp1^cKO: n=30 acini). Data are presented as mean±s.e.m. ***P<0.001. (E) Representative electron micrographs of wild-type and Blimp1^cKO day 6 4OHT-treated MEC 3D acini revealing alterations in the establishment of an apical-basal polarity in mutant acini compared with wild type, accompanied by dismantled tight junctions (1′ vs 1; arrowheads), fragmentation of the Golgi apparatus (2′ vs 2; arrows) and loss of apical villi.