Patterns of cell movement within the Dictyostelium slug revealed by cell type-specific, surface labeling of living cells (original) (raw)
Related papers
Cell, 1995
We present evidence that Dictyostelium slug tip cells, the pstA cells, may arise by positional differentiation, but at asite remote from that which they will eventually occupy. When first detectable, the pstA cells form a peripheral ring surrounding the other prestalk cell subtype, the pst0 cells, but subsequently move above the pstOcellstoform thetip. BecausepstAcell differentiation requires a lo-fold higher concentration of differention-inducing factor, the stalkcell inducer, the initial patterning seems likely to reflect the existence of a morphogenetic gradient. The subsequent redistribution of the two cell types is explicable by their different rates of chemotaxis to cyclic AMP. These results help reconcile the two apparently opposing views of pattern formation in Dictyostelium, that there is positional differentiation and that pattern formation occurs by cell sorting.
Analysis of cell movement during the culmination phase of Dictyostelium development
Development (Cambridge, England), 1996
Co-ordinated cell movement of tens of thousands of cells and periodic signals characterise the multicellular development of the cellular slime mould Dictyostelium discoideum. We investigated cell movement by analysing time-lapse video recordings made during the slug stage and the culmination phase of Dictyostelium development. Slugs viewed from the side showed an even, straight forward movement with the tip slightly raised in the air. Slugs that had migrated for a prolonged period of time either culminated or showed a behaviour best described as abortive culmination. Culmination is initiated by a local aggregation of anterior-like cells at the base of the slug at the prestalk-prespore boundary, where they form a stationary mass of cells. Prespore cells continue to move forward over this stationary pile and, as a result, are lifted into the air. The stationary group of anterior-like cells thereby end up to the back of the slug. At this point the slug either falls back on the agar sur...
Regulation of cell differentiation and pattern formation in Dictyostelium development
The International journal of developmental biology, 1994
Free-living cells of Dictyostelium discoideum aggregate to form a slug-shaped cell mass and differentiate into prestalk and prespore cells. The differentiation of prespore cells is characterized by expression of Dp87 gene, the earliest event of prespore differentiation. It encodes a protein which first appears in ER of aggregating cells in a precursor form, is then translocated to prespore vacuoles and modified to a mature form and finally exocytosed to constitute the sorus matrix. The transcription of Dp87 is regulated by the cis-acting region consisting of positive, prespore-specific, negative, non-prespore-specific and positive, cell-type-non-specific elements. Cells expressing Dp87 appear at random in early aggregation streams and centers and then sort out to the posterior part of the slug. Intercellular signals required for prestalk and prespore differentiation were investigated by incubation at a low cell density of disaggregated cells. cAMP is inhibitory at the first and seco...
Optical flow analysis of the ventral cellular layer of the migrating Dictyostelium discoideum slug
Microbiology, 1994
A digital image analysis system for extracting motion information from timevarying digital light microscopy images is presented. This system is then used to map out the movement profile of the surface layer of cells in contact with the substratum through the extracellular matrix (ECM) of the migrating Dictyostelium discoideum slug. From digital high magnification light microscopy images, the morphology of moving cells within the tail region of a young migrating wild-type WS380B slug is described, and compared with the morphology of streaming D. discoideum cells. It is shown that: (i) when the migrating tip of the slug touches the agar substrate, cells in the anterior ventral surface layer of the tip region slow dramatically; (ii) overall cell movement in the ventral surface layer of the migrating D. discoideum slug is slower than the movement of the slug as a whole; and (iii) in less than 10% of cases a wave of movement (groups of cells synchronously slowing down and then accelerating forward) propagates down the slug axis a t approx. 1.2 pm s-l. The time interval between waves may be related to the time interval between tip-to-substratum contact that is periodically re-established during normal WS380B slug migration after each aerial projection of the tip. Abbreviation: ECM, extracellular matrix. Ultimately, to understand how the slug of D. discoidezlm migrates, requires knowledge of how the cells within the slug move (Williams e t al., 1986; Breen & Williams,
Molecular and cellular biology, 1985
Polymorphisms of a major developmentally regulated prespore-specific protein (PsA) in Dictyostelium discoideum slugs are described. These polymorphisms allowed discrimination between PsA (found on the cell surface and in the extracellular matrix) and a similar extracellular but nonpolymorphic protein, ShA. The two proteins were also distinguished by their differing reactivities with a range of monoclonal antibodies and by their sensitivity to release from the sheath with cellulase. The results are discussed in terms of the molecular and genetic relationships between the cell surface and the extracellular matrix during development.
Movement of the multicellular slug stage of Dictyostelium discoideum: an analytical approach
Time-lapse video recordings of migrating multicellu-lar slugs of Dictyostelium discoideum were subjected to image analysis. A transient 'collar-like' structure was identified at the anterior end of the slug. This collar remains stationary in the wild-type strain WS380B; it is observed shortly after the advancing tip contacts the substratum. Stationary collars formed approximately every 12 min; they were matched with patterns revealed on the underside of slime trails with FITC-coupled monoclonal antibody MUD50. It is proposed that stationary collars are involved with the forward movement of the slug. The mutant strain HU2421 lacks the MUD50-epitope and forms collars which do not remain stationary but move backwards along the slug to collect at a 'waist' region. The slipping-collars observed in the mutant corre-lated with very slow migration rates. We propose that HU2421 moves slowly because it lacks traction.
Three-Dimensional Scroll Waves Organize Dictyostelium Slugs
Proceedings of The National Academy of Sciences - PNAS, 1992
To test the hypothesis that periodic signals and chemotaxis direct later morphogenesis in Dictyostelium discoideum, we investigated cell behavior and cell movement in slugs. Trails of neutral red-stained prestalk and anterior-like cells were recorded by high-resolution digital image processing. Neutral red-stained anterior-like cells in the prespore zone of slugs move straight forward in the direction of slug migration and, furthermore, show coherent periodic cell movement. In contrast, cells in the prestalk zone move along completely different trajectories. Prestalk cells move perpendicular to the direction of slug migration; that is, they rotate around the tip. The cell movement data show that the chemotactic signal in the slug propagates as a three-dimensional scroll wave in the prestalk zone and as a planar wave in the prespore zone. The different behavior of prestalk and prespore cells is most likely caused by a difference in the oscillatory properties of the two cell types. We...