[The ultrastructure of the cell center in the enterocytes of mouse embryos and newborn mice].
The centrosome structure was studied in differentiating small intestine enterocytes of mouse embryos (day 16 to 17 of gestation) and newborn mice. It is shown that fine structure of the centrosome in embryonic enterocytes differs from that found in cells of the adult mice. The centrosome of the crypt cells is more active: a greater number of cytoplasmic microtubules terminates there; mother centriole has two types of satellites; both centrioles are surrounded by fine fibrillar material. In 20% of crypt cells, replication of centrioles is observed. In the upper part of the villus of embryonic intestine, there still are two centrioles per cell, but they are located 3-7 um apart and devoid of any cytoplasmic microtubules attached to or directed toward them. In newborn mice, centrosomes of cells located at the bottom of the crypt are less active, as compared with centrosomes of embryonic cells. There are 1-3 satellites on mother centriole and few cytoplasmic microtubules closing to the centrosome. In 20% of cells from the bottom of the crypt centrioles are replicating. In the lateral part of the crypt, centrosome is inactive: centrioles are located 1-3 um apart and do not replicate. In the villus, centrioles undergo changes similar to those observed in the villus of adult mice. Centrioles loose portions of microtubule triplets. Near the top of the villus, only one centriole was found in two of 25 studied cells. In the enterocytes of the murine small intestine, centrioles are always located far from nuclei and close to the apical cell surface (1-3 um from the brush border). Centrioles never form a primary cilium and are not attached to the plasma membrane.
Komarova
Iu A
IuA
Vorob'ev
I A
IA
D000818:Animals; D000831:Animals, Newborn; D001345:Autoradiography; D002454:Cell Differentiation; D002502:Centrioles / Q000648:ultrastructure; D003593:Cytoplasm / Q000648:ultrastructure*; D007421:Intestine, Small / Q000196:embryology* / Q000648:ultrastructure*; D051379:Mice; D008854:Microscopy, Electron; D013997:Time Factors
Ul'trastruktura kletochnogo tsentra v énterotsitakh u émbrionov i novorozhdennykh mysheĭ.