Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
???displayArticle.abstract???
The dorsal half of bisected Xenopus laevis embryos can regenerate a well-proportioned organism on a smaller scale. A new study indicates that the removal of ventraltissue generates a steeper Chordin gradient by reducing Sizzled, a secreted inhibitor of Tolloid chordinases.
Figure 1. Extracellular protein interactions in Xenopus dorsal-ventral patterning.
(A) Chordin inhibits BMPs, which activate expression of Sizzled, an inhibitor of Tolloid
proteases that degrades Chordin. (B) The dorsal-ventral network consists of many components
under opposite transcriptional control by BMPs [7]. Crescent is a Sizzled homolog
expressed in the Spemann Organizer [13]. (C) A simplified pathway in which Chordin and
Sizzled regulate each other [8]. The in situ hybridization in the background illustrates that
chd and szl mRNAs are expressed at opposite poles of the mid-gastrula [4]. The arrows indicate
direct protein�protein interactions in black, transcriptional regulation by BMP signaling in
blue, and diffusion (flux) of Chordin/BMP in red.
Figure 2. Chordin and Sizzled are key
regulators of dorsal-ventral patterning.
Depletion of Chordin or Sizzled with morpholinos
(MOs) results in identical high-BMP
phenotypes marked by an expanded ventral
domain of sizzled mRNA expression.
References :
Inomata,
Scaling of dorsal-ventral patterning by embryo size-dependent degradation of Spemann's organizer signals.
2013, Pubmed,
Xenbase
Inomata,
Scaling of dorsal-ventral patterning by embryo size-dependent degradation of Spemann's organizer signals.
2013,
Pubmed
,
Xenbase