Fig. 6. Altered general morphology and morphometric parameters of COUP-TFI-deficient primary neurons. (A-G'') All the neurons were labelled with an antibody against tyrosinated -tubulin (green) and rhodamine-phalloidin for actin (red). (A''-G'') Merged figures in which blue staining (DAPI) reveals the nucleus. (A-B'') After 12 hours of culture, COUP-TFI^null neurons show an abnormal distribution of actin filaments (arrows in B') and no or very little protrusions (arrowheads in B''). (C) Graph showing the percentage of neurons that display a spherical phenotype at different hours after plating. (D-E'') After 24 hours in culture, COUP-TFI^null neurons have extended some neurites; however, they present a curled and abnormal growth pattern (arrow in E''). The arrowheads in E'' indicate the ectopic presence of protrusions. (F-G'') After 48 hours in culture most of the COUP-TFI^null neurons do have a more elongated axon; however, these neurons display numerous short filopodial extensions (arrowheads in G''), and axons tend to curl abnormally (arrow in G''). The red arrowhead indicates abnormal accumulation of tubulin- and actin-rich structures around the nucleus. Scale bars: 10 µm in A-B''; 20 µm in D-G''. NULL, COUP-TFI^null neurons; WT, wild-type neurons.