XB-IMG-135196
Xenbase Image ID: 135196
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Supplementary Figure 1. Summary of this paper (A) Schematic presentation of gene expression patterns in Xenopus mid-gastrula embryos. Expression patterns of head organizer genes (1, 2) and non-head organizer genes (3Y6) are shown in head, notochord, and posterior mesoderm (indicated by dotted lines) or neural genes (7) in dorsal ectoderm. Some expression patterns were referred to Xenbase (http://www.xenbase.org/common/). (B) Model for Otx2 functions as a molecular landmark of the head. Otx2 is involved in activation of anterior
genes (head organizer genes) while repressing the expression of the posterior/ventral genes (trunk
genes) within the same cells. Otx2 and Lim1 together with indicated transcriptional factors bind to
cis-regulatory modules (CRMs) containing Lim1Ybinding motifs (type I CRMs), which are found
among head organizer genes, such as gsc, cerberus, chordin and crescent, as suggested by reporter
gene assays 1,2,3, animal cap assays4,5 and this study. Otx2 binding to chordin and crescent CRMs is probably indirect because there are no Otx2 binding motifs (bicoid/P3C) in these CRMs. The co-activator, p300, binds to the CRMs, but the factor directly binding to p300 is unknown. Otx2, Gsc, and TLE bind to CRMs containing multiple bicoid/P3C binding motifs (type II CRMs) located within the trunk genes. Otx2 and Gsc possibly form a heterodimer on P3C sites,6 and bind directly to the co-repressor, TLE/Groucho.7,8 Thus, Otx2 influences expression of a battery of genes, each of which
interprets the input for activation or repression via various CRMs to provide head identify. HD,
homeodomain; RD, transrepression domain; AD, transactivation domain. Image published in: Yasuoka Y et al. (2014) Copyright © 2014. Image reproduced with permission of the Publisher, Macmillan Publishers Ltd. Larger Image Printer Friendly View |