Experimental modulation of intercellular cohesiveness: Reversal of tissue assembly patterns

摘要: After cell sorting or the fusion of tissue fragments, chick embryonic liver populations typically tend to surround heart populations. We show here that by varying ratio cells in mixed reaggregates—or relative sizes and reaggregates reaggregate-fusions—the inside vs outside positions adopted these two can be reversed. By contrast, undissociated fragments envelop irrespective their sizes. Our experiments reveal sources position-reversal behavior. (1) Tryptic dissociation-reaggregation causes become more externalizing; (2) vitro culture conditions cause internalizing. Previous evidence indicates less cohesive ones. It appears that, regardless heart: ratio, reaggregated are initially than cells, but during subsequent culturing population. This tissue-specific change cohesiveness results behavior, detection which is, for strictly mechanical reasons, facilitated variations phase ratio. A critical test reported confirms this interpretation. Position reversal behavior illustrates how a intercellular course normal differentiation could initiate morphogenetic movement.