Table 1.

krc mutants show reduced numbers of cilia compared with controls

Tissue	Control	Krc Mutant
e8.25 Node	25.9 ± 4.88	5.25 ± 1.67
e10.5 Forelimb mesenchyme	18.8 ± 3.47	6.96 ± 2.76
e12.5 Lung mesenchyme	19.7 ± 5.27	7.17 ± 2.87
e18.5 Lateral brain ventricles: lateral side	13.4 ± 1.98	2.42 ± 1.31
e18.5 Lateral brain ventricles: medial side	10.6 ± 2.84	7.25 ± 1.54

Cilia were counted in several embryonic tissues. We observed a two- to five-fold reduction in the number of cilia in most tissues. For e8.25 nodal cilia, whole or partial cilia were counted in a 144 square micron area. Three mutants and four controls were used and cilia in 1–3 SEM images per embryo were counted. For e10.5 limbs, e12.5 lung mesenchyme and e18.5 lateral brain ventricles, cilia were marked using an antibody against Arl13b on frozen sections. For lungs and limbs, we counted cilia in a 1.6 mm² area and for brains, cilia were counted along a 40 μm length of the ventricle lumen. Three mutant and three control embryos were assayed for cilia formation in each of these tissues, with four (brains), six (lungs) or eight (limbs) images analyzed per embryo.