DEV019877 Supplementary Material

Files in this Data Supplement:

• Supplemental Figure S1 -

  Fig. S1. Notch signal standard time. A Notch standard time (phases I-III) was defined by the location of the Notch active domain in the posterior PSM. Phase I is defined as the stage at which the wave of oscillating Notch activity exists at the posterior PSM. Phase II is the stage at which oscillating Notch activity moved to the intermediate PSM. Phase III is the stage at which Notch activity reached the anterior PSM, and a new wave has just started at the end of the posterior PSM.

• Supplemental Figure S2 -

  Fig. S2. Mesp2 protein and Tbx6 protein are completely segregated. (A,B) Double immunostaining of the Mesp2 and Tbx6 proteins of E10 caudal tissue. These two expression domains are segregated and form a clear border (indicated by the dashed lines). Some cells were found to still express Tbx6 in the Mesp2 expression domain, but lacked Mesp2 expression (indicated by the dotted circles).

• Supplemental Figure S3 -

  Fig. S3. Mesp2 expression is not directly regulated by Wnt signaling. Analysis of the Wnt signaling pathway. (A-C) The spatial relationship between Mesp2 (green, mRNA probe) and Msgn1 (magenta). Arrows indicate posterior limits of Mesp2 transcription. This embryo was designated as phase I. (D,E) Msgn1 expression revealed by whole-mount in situ hybridization in wild-type (D, n=3) and Mesp2-null (E, n=2) embryos. Lateral views.

• Supplemental Figure S4 -

  Fig. S4. Proposed models for the mechanisms that generate rostro-caudal patterning within a somite. (A-F) The spatio-temporal relationship between Mesp2 and Tbx6 (A,C,E are the same as the images shown in Fig. 3F,I,C) and between Notch activity (NICD) and Tbx6 (B,D,F) during one cycle of somitogenesis. An interpretation of these data is shown schematically below each image. (G) Model of the genetic cascades leading to the establishment of rostral-caudal patterning within a somite.