Short historical survey of pattern formation in the endo-mesoderm and the neural anlage in the vertebrates: the role of vertical and planar inductive actions

Abstract

After some introductory remarks about vertical versus horizontal inductive interactions and about planar versus homoiogenetic induction, the author discusses: a) the historical development of the more recently studied endo-mesoderm induction in the Urodeles and in the anuran Xenopus laevis, b) the possible causal relationship between endo-mesoderm induction and the initiation of the gastrulation process, and c) the older history of the regional neural induction as initially studied in the Urodeles and only recently analysed in the anuran Xenopus laevis. The essential vertical interaction in the neural induction process both in urodelian and in anuran amphibians is emphasized.

Kremen proteins interact with Dickkopf1 to regulate anteroposterior CNS patterning

“…Furthermore, inhibition of BMP and nodal signalling is a prerequisite for anterior neural induction, and this antagonism is mediated by secreted antiBMPs (noggin, chordin and follistatin) (Smith and Harland, 1992;Hemmati-Brivanlou et al, 1994;Sasai et al, 1994;Bachiller et al, 2000) (reviewed by Harland and Gerhart, 1997;Streit and Stern, 1999) and anti-nodals (antivin, Cerberus and lefty) (Fainsod et al, 1997;Meno et al, 1999;Piccolo et al, 1999;Thisse and Thisse, 1999;Thisse et al, 2000) (reviewed by Schier and Shen, 2000).These factors are emitted from the Spemann organiser of amphibia and its equivalents in other vertebrates. As for anterior CNS formation, posterior CNS formation also depends on BMP inhibition, but in addition requires posteriorising signals such as FGF, retinoic acid and Wnt (Gilbert and Saxen, 1993;Doniach and Musci, 1995;McGrew et al, 1995;Nieuwkoop, 1997;Sasai and de Robertis, 1997;Dupe and Lumsden, 2001).…”

21st Century neontology and the comparative development of the vertebrate skull

“…Work over the past 15 years, fortunately, has made the conflux of pre-and postgenerative molecular and cellular influences of the AME on head development less caliginous if no less byzantine (see de Souza and Niehrs, 2000;Kiecher and Niehrs, 2001;Roessler and Muenke, 2001;Schier, 2003;Tam et al, 2003). As noted above, the pre-gastrulation, pre-organizer-influenced epiblast is a polarized tissue, in large part as a consequence of developmental events initiated by the germinal establishment of asymmetry and resulting in the focalization of "determinants" that subsequently induce the formation of the vertebrate Organizer itself (Nieuwkoop, 1985(Nieuwkoop, , 1997Eyal-Giladi, 1997;Joubin and Stern, 1999;Beddington and Robertson, 1999;Brennan et al, 2001;Gerhart, 2001;Kiecher and Niehrs, 2001). These "determinants" eventually result, directly or indirectly, in the graded activity (principally in the epiblast) of the transforming growth factor (TGF-␤) -related secreted signaling molecule Nodal (Brennan et al, 2001;Gerhart, 2001;Bertocchini and Stern, 2002;Schier, 2003;Tam et al, 2003).…”

Antero-posterior patterning of the vertebrate digestive tract: 40 years after Nicole Le Douarin's PhD thesis

“…During AIP or CIP progression, they must acquire a pattern that is similar to that of the dorsal cells of the same level which derive from midline endoderm and have roughly maintained their position relative to the notochord and neural tube. In Xenopus, as the suprablastoporal lip of the blastopore forms the dorsal gut tube and the subblastoporal lip forms its ventral aspect, A-P identity also needs to be coordinated (Keller, 1975, Keller, 1976, Nieuwkoop, 1997. In Zebrafish, organ domains are segregated prior to gut tube formation (Wallace and Pack, 2003).…”