A Model of Primitive Streak Initiation in the Chick Embryo

✍ Scribed by KAREN M. PAGE; PHILIP K. MAINI; NICHOLAS A.M. MONK; CLAUDIO D. STERN

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 314 KB
• Volume: 208
• Category: Article
• ISSN: 0022-5193
• DOI: 10.1006/jtbi.2000.2229

✦ Synopsis

Initiation of the primitive streak in avian embryos provides a well-studied example of a pattern-forming event that displays a striking capacity for regulation. The mechanisms underlying the regulative properties are, however, poorly understood and are not easily accounted for by traditional models of pattern formation, such as reaction}di!usion models. In this paper, we propose a new activator}inhibitor model for streak initiation. We show that the model is consistent with experimental observations, both in its pattern-forming properties and in its ability to form these patterns on the correct time-scales for biologically realistic parameter values. A key component of the model is a travelling wave of inhibition. We present a mathematical analysis of the speed of such waves in both di!usive and juxtacrine relay systems. We use the streak initiation model to make testable predictions. By varying parameters of the model, two very di!erent types of patterning can be obtained, suggesting that our model may be applicable to other processes in addition to streak initiation.