||Figure 1. Expression and activity of the two dermatan sulfate epimerases inXenopus embryos. (A) Protein structures. Xenopus DS-epi1 and DS-epi2 contain cleavable signalpeptides (arrows), an epimerase domain, and two transmembrane domains. In DSepi1, the catalytic residues His-205, Tyr-261, and His-450 are indicated, which are also conserved in DS-epi2. DS-epi2 contains an additional sulfotransferase-like domain.
(B) RT-PCR analysis. Histone H4 is used as the loading control. A minimum of two experiments (n≥2) was performed with three independent biological samples. (C) DS epimerase activity in early Xenopus embryos. Mean ±SDEV from triplicates.
Two independent experiments. (D-E’) Whole-mount in situ hybridization of neurula embryos in the dorsal view (D,E) and transversal section (D’,E’). The arrowheads label the pre-migratory CNC cells. The dashed looped line demarcates the Snail2+ CNC embedded in the Dse
expression domain. (F) qPCR analysis in CNC explants at stage 18. c-Myc was used as a CNC cell marker. Note that Dse but not Dsel mRNA is be detected. Mean ±SDEV from triplicates. Number of biological replicates n=4. (G-I’) Tailbud embryos in the lateral view (G-I) and horizontal section (G’-I’). Note that Dse and Dsel overlap with Twist expression in migrating CNC cells. Section planes are indicated with dashed straight lines. br, branchial arch segments; CNC, cranial neural crest; epi, epidermis; hy, hyoid segment; ma, mandibular segment; no, notochord; SP, signal peptide; TM, transmembrane domains.