Avian marginal zone cells function as primitive streak inducers only after their migration into the hypoblast

Hefzibah Eyal-Giladi, Tamar Lotan, Tovi Levin, Orit Avner, Jacob Hochman

Research output: Contribution to journalArticlepeer-review


Hypoblast cells of posterior marginal zone origin have been shown previously to be the inducers of primitive streak in the avian embryo. Here we checked: (1) whether the above cells acquire their inductivity while still within the marginal zone; (2) can inductivity be found in supernatants of defined blastodermic regions; (3) can differences in the electrophoretic pattern be shown between inducing and non-inducing tissue fragments and their conditioned media. which might give a clue as to what the inductive substance is. The following observations were made: 1. (a) Stage X chick posterior marginal zone cells prior to their migration into the hypoblast do not induce a primitive streak, when applied to a stage XIII competent epiblast central disc. (b) A posterior marginal zone fragment, when applied to an epiblast central disc, even after being preincubated for up to 9 hours in vitro, is still non-inductive. (c) Mechanically fragmented stage X posterior marginal zones when applied as a layer to epiblast central discs are non-inductive. (d) Hypoblastic tissue in strip form induces a primitive streak. 2. Competent stage XIII epiblast central discs (chick) were incubated for 2 hours in supernatants of stage XIII epiblasts or hypoblasts. Whereas no inductive effect was exerted by the epiblast supernatant, primitive streaks developed in about 50% of the epiblast central discs incubated in the hypoblast supernatant. 3. Electrophoretic analysis (quails) reveals a protein of 28x10-3 M(r) that is enriched in both hypoblastic tissue and its incubation medium and not in the epiblast + marginal zone + area opaca and their incubation medium. These findings suggest a possible correlation between this protein and the induction process.

Original languageEnglish
Pages (from-to)2501-2509
Number of pages9
JournalDevelopment (Cambridge)
Issue number9
StatePublished - Sep 1994
Externally publishedYes


  • Avian marginal zone
  • Electrophoretic study
  • Hypoblast
  • Primitive streak induction

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology


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