Fig. 2. Mesp2 transcription occurs at the anterior end of the Tbx6 expression domain. (A-J) Spatio-temporal changes in the Mesp2 transcription pattern during somitogenesis. Double staining of Mesp2 and NICD (see Fig. 1E-N) or of Mesp2 and Tbx6 (A-F) was conducted using a single mouse embryo for each phase. (A,B) Phase II, (C,D) phase III and (E,F) phase I. The staining patterns for B,D,F are also shown schematically. (G,H) Magnified images of C,D. (I,J) Magnified images of E,F. The transcriptional states in I and J were roughly estimated using the subcellular localization pattern of the Mesp2 transcripts and are shown in the right-hand panel.