Mediolateral cell intercalation occurs in the SAZ during GBE.

<p>Time series from fluorescent live imaging of a <i>Tribolium</i> embryo expressing NLS-tdEos showing the SAZ during abdominal segment formation. Coloured points mark tracked nuclei. During the timelapse, nuclei underwent apicobasal movement, but I observed no cell delamination. Note that the same embryo is shown in <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.2005093#pbio.2005093.g003" target="_blank">Fig 3A–3F</a>. The first frame of the timelapse was defined as time point 0. The embryo is oriented based on polarity of the visible region of the germband. Panels show maximum intensity projections of 15 μm to specifically show the germband. The scale bar is 50 μm. ant, anterior; GB, germband; GBE, germband extension; lat, lateral; med, medial; NLS-tdEos, <i>nuclear localisation signal-tandem Eos</i>; post, posterior; SAZ, segment addition zone.