The anterior-like cells in Dictyostelium are required for the elevation of the spores during culmination

Abstract

Shortly after initiation of Dictyostelium fruiting body formation, prespore cells begin to differentiate into non-motile spores. Although these cells lose their ability to move, they are, nevertheless, elevated to the tip of the stalk. Removal of the amoeboid anterior-like cells, located above the differentiating spores in the developing fruiting body, prevents further spore elevation although the stalk continues to elongate. Furthermore, replacement of the anterior-like cells with anterior-like cells from another fruiting body largely restores the ability to lift the spores to the top of the stalk. However, if amoeboid prestalk cells are used to replace the anterior-like cells, there is no restoration of spore elevation. Finally, when a droplet of mineral oil replaces differentiating spores, it is treated as are the spores: the mineral oil is elevated in the presence of anterior-like cells and becomes arrested on the stalk in the absence of anterior-like cells. Because a similar droplet of mineral oil is totally ignored by slug tissue, it appears that there is a dramatic transformation in the treatment of non-motile matter at this point in Dictyostelium development.

An anatomy ontology to represent biological knowledge in Dictyostelium discoideum

“…Prespore cells move to the top of the stalk [63,65] and, terminally differentiate into spores. At this stage, the spores are contained in a more compact structure, the sorus of the late culminant (DDANAT:0000061).…”

Progress and perspectives in signal transduction, actin dynamics, and movement at the cell and tissue level: lessons fromDictyostelium

“…This then starts a stalk-forming process directed downward, resulting in the formation of the basal disc, stalling fusion and successive elongation of the stalk [119] (figures 1 and 9). It has been suggested that the spore mass is lifted up the stalk by the combined crawling action of the lower-and upper-cup cells [120]. There has been one detailed model of culmination based on the cellular Potts model that captures some of the essential elements [121,122], but many questions, especially the role of cellular and tissue mechanics in this process, remain unresolved.…”

A new Dictyostelium prestalk cell sub-type

“…The existence of two classes of upper cup cells, those that express rtaA and those that express ecmB , implies a possible functional heterogeneity. The only function thus far ascribed to the upper cup is as a cellular motor that elevates the spore head up the stalk (Sternfeld, 1998). It will be of interest to know whether PstU cells participate in this process.…”

“…The ALCs were originally identified by staining with vital dyes such as neutral red and significant advances in understanding their function has been made by marking them in this way, e.g. the demonstration that the upper cup behaves like a motor that lifts the spore head up the stalk (Sternfeld, 1998). However, for many purposes, markers of gene expression are preferable to vital dyes and they provide the evidence for multiple prestalk and ALC sub-types.…”