Premium
Patterns of oriented cell division during the steady‐state morphogenesis of the body column in hydra
Author(s) -
Shimizu Hiroshi,
Bode Patricia M.,
Bode Hans R.
Publication year - 1995
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/aja.1002040402
Subject(s) - biology , lernaean hydra , mitosis , cell division , anatomy , endoderm , ectoderm , morphogenesis , process (computing) , microbiology and biotechnology , displacement (psychology) , cell , embryo , cellular differentiation , embryogenesis , genetics , computer science , operating system , psychology , gene , psychotherapist
In an adult hydra, the tissue of the body column is in a dynamic state. The epithelial cells of both layers are constantly in the mitotic cycle. As the tissue expands, it is continuously displaced along the body axis in either an apical or basal direction, but not in a circumfer‐ential direction. Using a modified whole mount method we examined the orientation of mitotic spindles to determine what role the direction of cell division plays in axial displacement. Surprisingly, the direction of cell division was found to differ in the two epithelial layers. In the ectoderm it was somewhat biased in an axial direction. In the endoderm it was strongly biased in a circumferential direction. For both layers, the directional biases occurred throughout the length of the body column, with some regional variation in its extent. As buds developed into adults, the bias in each layer increased from an almost random distribution to the distinctly different orientations of the adult. Thus, to maintain the observed axial direction of tissue displacement, rearrangement of the epithelial cells of both layers must occur continuously in the adult as well as in developing animals. How the locomotory and contractile behavior of the muscle processes of the epithelial cells may effect changes in cell shape, and thereby influence the direction of cell division in each layer, is discussed. © 1995 wiley‐Liss, Inc.