The geometry of early cleavage is modified in this species such that the micromeres and the early embryonic pattern of msp 130 expression is absent and an unusually large number of mesenchyme cells enter the blastocoel, where they begin directly forming the adult skeleton.
Unequal divisions at the third cleavage increase the number of primary mesenchyme cells in sea urchin embryos.
cordatus, the blastula - which is filled with mesenchyme cells - is in fact a stereoblastula.
As the archenteron approaches the wall of the animal region, pseudopodia-forming cells become disengaged from the archenteron and form a mass of secondary mesenchyme cells that spread over the inner surface of the adjacent ectoderm (see Burke, 1990; Burke et al.
Therefore, fetal mouse UGS mesenchyme cells provide an informative model of endocrine control of prostate development.
Cells were treated with DHT rather than testosterone to control for potential treatment effects on the intracellular concentration of this high-affinity ligand for the androgen receptor, which is formed from testosterone in UGS mesenchyme cells in vivo, and also to avoid the intracellular metabolism of testosterone to [E.
Seven days after bisection (28 days after fertilization), the aggregation of mesenchyme cells
(described above) seen in the anterior portions of the larvae appeared to be involved in development of a new pair of coelomic pouches that evaginated from the anterior portion of the newly formed "digestive tube" (Fig.
During secondary invagination, a population of secondary mesenchyme cells
(SMCs) connect the archenteron tip to the inner surface of the apical plate and exert the force to pull up the archenteron (Dan and Okazaki, 1956; Hardin, 1988).
expression of the transgene is never observed in primary mesenchyme cells
(PMCs) derived from the vegetal micromeres.
Expression of SUM-1 in the intact embryo precedes overt myogenic differentiation of the secondary mesenchyme cells
as determined by RNAse protection analyses using riboprobes to SUM-1 and myosin heavy chain (MHC) and labeling of cells by indirect immunofluorescence (4, 5).
Stereo views of sequential slices, generated from limited sets of serial optical sections, bring out further details of the cellular organization, including the regular pavement-like arrangement of the circumoral epithelium and the shape of the mesenchyme cells
that were masked by the overlapping complex structure in the whole embryo.