Abstract
A pattern of two tissue types exists in the Dictyostelium slug. Contained within the posterior tissue are anterior-like cells which comprise about 10% of the developing cell mass. For more than 72 hr of slug migration the proportion of these cells is closely regulated. They are randomly distributed along the anterior-posterior axis but about twice as many are localized in the ventral portion of the slug posterior than in the dorsal portion. As the slug begins to form a fruiting body, the anterior-like cells sort out into two groups. One group moves toward the anterior region and one toward the prebasal disc region. In the mature fruiting body the anterior-like cells remain as undifferentiated amoebae at the apex and base of the sorus. Removal of anterior tissue from a slug initiates two events. (1) Some of the anterior-like cells, probably guided by chemotaxis to cyclic AMP, sort out from the posterior tissue. (2) Some prespore cells redifferentiate into anterior-like cells. These events result in the regeneration of a new anterior-posterior pattern after 2 hr and the reestablishment of the original proportions of each cell type by about 8 hr. Furthermore, while the anterior-like cells which lie in slug posteriors remain as amoebae in fruiting bodies, the anterior-like cells which form the anteriors of regenerated slugs subsequently become stalk cells. Thus, it appears that for a cell to differentiate as a stalk cell, it must first be exposed to some form of signal which is present in both the anterior and prebasal disc regions.
Dokumententyp: | Zeitschriftenartikel |
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Fakultät: | Biologie |
Themengebiete: | 500 Naturwissenschaften und Mathematik > 570 Biowissenschaften; Biologie |
URN: | urn:nbn:de:bvb:19-epub-3369-8 |
Dokumenten ID: | 3369 |
Datum der Veröffentlichung auf Open Access LMU: | 21. Apr. 2008, 14:29 |
Letzte Änderungen: | 04. Nov. 2020, 12:47 |