Figure 1. Loss of Function of the Dorsally Expressed Protein ONT1 Causes Dorsalization of the Embryo(A) Structure comparison of ONT1 with other Olfactomedin-class proteins. SP, signal peptide; CC, coiled-coil domain; OLF, Olfactomedin domain.(B–D) Whole-mount in situ hybridization of ONT1 expression at the early gastrula ([B]; sagittal section), midgastrula ([C]; sagittal section), and neurula ([D]; cross-section) stages. Brackets (B and C) show ONT1 expression in the dorsal axial tissues. The arrowhead in (B) indicates the dorsal lip. so, somite; not, notochord.(E and F) Radial injection of ONT1-MO (F) at the four-cell stage.(G–N) Effects of ONT1-MO injection at the four-cell stage on DV markers analyzed in the gastrula. ONT1-MO (25 ng) caused expansion of the dorsal axial markers Gsc ([G and K]; anterior view; stage 13), Chordin ([H and L]; dorsal view; stage 13), and Shh ([I and M]; dorsal view; stage 13), whereas expression of the ventral marker Szl was reduced ([J and N]; vegetal view; stage 12).(O–R) Dorsalization induced by ONT1-MO (25 ng) injection at the four-cell stage was rescued by coinjecting a small amount (4 pg) of MO-resistant ONT1 RNA (ONTa(mut)). The expansion of dorsal markers Gsc (52%, n = 21), Chordin (54%, n = 13), and Shh (79%, n = 14) was reversed by ONTa(mut) (O–Q).(R) The reduction of Szl (70%, n = 20) was rescued by ONTa(mut).(S and T) ONT1-MO was injected specifically into two dorsal (S) or ventral (T) blastomeres at the four-cell stage. Gsc expression is shown in anterior view. Insets show the expression of coinjected GFP in dorsal (S) and ventral (T) blastomere progenies in the corresponding embryos.
Image published in: Inomata H et al. (2008)
Copyright © 2008. Image reproduced with permission of the Publisher, Elsevier B. V.
| Gene | Synonyms | Species | Stage(s) | Tissue |
|---|---|---|---|---|
| olfml3.L | ont1 | X. laevis | Throughout NF stage 10.5 | deep involuted dorsal mesoderm endomesoderm |
| olfml3.L | ont1 | X. laevis | Throughout NF stage 12 | deep involuted dorsal mesoderm |
| olfml3.L | ont1 | X. laevis | Throughout NF stage 18 | notochord somite paraxial mesoderm axial mesoderm |
| gsc.L | goosecoid, gsc-a, gsc-b, Xgsc | X. laevis | Throughout NF stage 13 | dorsal marginal zone upper blastopore lip |
| chrd.S | chd, chordin, chrd.1, LOC108716939, X-chordin | X. laevis | Throughout NF stage 13 | axial mesoderm neural groove |
| shh.L | hedgehog, vhh-1, X-SHH, Xhh, xshh | X. laevis | Throughout NF stage 13 | axial mesoderm neural groove |
| szl.L | frzb3, secreted frizzled, sizzled, xszl | X. laevis | Throughout NF stage 12 | ventro-lateral marginal zone |
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