Physiological gradients in development. A possible role for messenger ribonucleoprotein.

Abstract

This chapter discusses a possible role for messenger ribonucleoprotein. It describes the early embryonic interactions. It presents a unifying concept for the basis of animalization and vegetalization. Vegetalizations involve the passage of ribonucleoproteins (RNPs) to the induced cells or the protection of RNPs present there. However, animalization involves reduction of bonds within RNP and release of the RNA for translation though the natural inducer(s) responsible for this are not identified. Several developmental systems have been reviewed in terms of some new hypotheses for morphogenetic control and interactions. Stable RNPs are produced in such systems. Through their information content and the pattern of control of their translation, they provide spatial information within the system. These RNPs are bonded by disulphide, sulphamino, and other oxidized groups, so that breaking them to release the RNA for translation requires reduction. Therefore, the distribution of undefined metabolic factors leading to a high reduction rate provides a second kind of spatial information.