Cell patterning.

  • Symposium on Cell Patterning (1974 : London, England)
Date:
1975
Catalogue details

Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Cell patterning. Source: Wellcome Collection.

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    The structure and properties of a compartment border: the intersegmental boundary in PETER A. LAWRENCE MRC Laboratory of Molecular Biology, University Postgraduate Medical School, Cambridge Abstract García-Bellido et al. have described how groups of cells in developing Drosophila become subdivided into ‘compartments’. Cells within any compart ment have rigid prospective fates such that, while their progeny may give rise to variable regions within a compartment, they can never generate cells in any other compartment. Analysis of the position and shapes of clones allows definition of the compartment boundaries. I report studies on a compartment boundary (likewise demonstrated by clonal analysis) in the hemipteran insects Oncopeltus and Rhodnius. The advantage of this border is that it can easily be identified in the light and electron microscopes. There is an abrupt change of cell shape at the border, which has been analysed by means of serial electron microscope sections. The types of cell junctions at the border and elsewhere are compared and shown to have no qualitative differ ences. The border is an effective barrier to the growth of peripheral sensory axons, although not apparently to dendrites. The intersegmental boundary allows passage of information relating to cuticle deposition, wounding response, tracheolar movement and intercellular coupling. Making wounds across the border leads to greater effects on polarity of epidermal cells than making similar wounds elsewhere on the tergites. COMPARTMENTS Methods for analysing growth of insects by means of genetically marked clones have been developing rapidly. The ability of X-rays to induce a high rate of somatic crossing over, as well as the existence of mutants which mark the cuticular secretion of each cell, has permitted a sophisticated analysis of cell lineage in Drosophila. Irradiation of staged eggs and larvae has shown that, progressively during development, groups of cells acquire particular properties which affect their behaviour and the behaviour of the clones of progeny that each cell generates. This is expressed partly in the shape of the clones: for example, it was noted (García-Bellido 1968; Bryant 1970; García-Bellido &