Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)

Editor

Personal info

View

About

Terms

Javascript disabled

Please enable Javascript support in your browser to use this application.

Instructions on how to enable JavaScript on different browsers can be found here: http://www.google.com/support/bin/answer.py?answer=23852.

[edit this page]

Gene Review:

egr2 - early growth response 2 (Krox-20 homolog)

Xenopus laevis

Synonyms: Krox-20, XKr20, XKrox-20, egr2-A, krox20

Bradley, L.C. et al., Umbhauer, M. et al., van der Wees, J. et al., Watanabe, T. et al., Lamb, T.M. et al., et al.

Welcome! If you are familiar with the subject of this article, you can contribute to this open access knowledge base by deleting incorrect information, restructuring or completely rewriting any text. Read more.

High impact information on egr2-A

In these, four position-specific neural markers (engrailed-2, Krox-20, XlHbox 1, and XlHbox 6) were expressed in the ectoderm in the same A-P order as in the embryo [1].
Mauthner cell multiplications in the posterior hindbrain, and (both anteriorly and posteriorly) expanded Krox-20 expression domains indicated (partial) transformation of a large part of the hindbrain into (at least partial) rhombomere 3, 4 and/or 5 identity [2].
The response of later gastrula (stage 11-12) ectoderm to bFGF changes so that Krox 20 and En-2 are induced by bFGF alone, while induction of more posterior tissue marked by Hox B9 is eliminated [3].
In contrast to t-R4, platelet derived growth factor (PDGF)-dependent FGFR-1 activation in neuralized ectodermal cells expressing a chimeric PDGFR-FGFR-1 receptor results in the expression of Krox20 and Hoxb9 [4].
Krox-20, originally identified as a member of "immediate-early" genes, plays a crucial role in the formation of two specific segments in the hindbrain during early development of the vertebrate nervous system [5].

Biological context of egr2-A

In neuralized ectoderm, expression of t-R4 causes the up-regulation of the midbrain markers En-2 and Wnt-1, but not of the hindbrain nor the spinal cord markers Krox20 and Hoxb9 [4].

Anatomical context of egr2-A

Krox-20 has been implicated in the segmental patterning of the hindbrain in the mouse by its expression prior to segment formation in alternating domains, which later correspond to r3 and r5 [6].
We speculate that this may reflect a distinct route of neural crest migration due to anatomical differences between these systems, rather than a difference in the site of origin of Krox-20-expressing crest [6].

Other interactions of egr2-A

Expression in embryos of a dominant interfering form of xGCNF reduces the expression of endogenous En-2 and Krox-20 [7].

Analytical, diagnostic and therapeutic context of egr2-A

Using whole-mount in situ hybridization, we compare the expression of three neural markers, N-CAM, En-2 and Krox-20 in activin-treated ectoderm from control and ventralized embryos [8].

References

Planar induction of anteroposterior pattern in the developing central nervous system of Xenopus laevis. Doniach, T., Phillips, C.R., Gerhart, J.C. Science (1992) [Pubmed]
Inhibition of retinoic acid receptor-mediated signalling alters positional identity in the developing hindbrain. van der Wees, J., Schilthuis, J.G., Koster, C.H., Diesveld-Schipper, H., Folkers, G.E., van der Saag, P.T., Dawson, M.I., Shudo, K., van der Burg, B., Durston, A.J. Development (1998) [Pubmed]
Fibroblast growth factor is a direct neural inducer, which combined with noggin generates anterior-posterior neural pattern. Lamb, T.M., Harland, R.M. Development (1995) [Pubmed]
Signaling specificities of fibroblast growth factor receptors in early Xenopus embryo. Umbhauer, M., Penzo-Méndez, A., Clavilier, L., Boucaut, J., Riou, J. J. Cell. Sci. (2000) [Pubmed]
Functional role of a novel ternary complex comprising SRF and CREB in expression of Krox-20 in early embryos of Xenopus laevis. Watanabe, T., Hongo, I., Kidokoro, Y., Okamoto, H. Dev. Biol. (2005) [Pubmed]
The structure and expression of the Xenopus Krox-20 gene: conserved and divergent patterns of expression in rhombomeres and neural crest. Bradley, L.C., Snape, A., Bhatt, S., Wilkinson, D.G. Mech. Dev. (1993) [Pubmed]
A role for xGCNF in midbrain-hindbrain patterning in Xenopus laevis. Song, K., Takemaru, K.I., Moon, R.T. Dev. Biol. (1999) [Pubmed]
Ventral ectoderm of Xenopus forms neural tissue, including hindbrain, in response to activin. Bolce, M.E., Hemmati-Brivanlou, A., Kushner, P.D., Harland, R.M. Development (1992) [Pubmed]

Contributions to this collaborative article are from individual authors of WikiGenes or mined by the WikiGenes Data Mining Engine from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.About WikiGenes Open Access Licence Privacy Policy Terms of Use apsburg

The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.