Correlation between the expression of the HNK-1 epitope and cellular invasiveness in prestreak epiblast cells of chick embryos.
During avian gastrulation, certain cells present in the epiblast layer ingress through the basement membrane sealing the basal surface of themselves. Previously we reported that chick prestreak epiblast cells show two different behavioral phenotypes upon reconstituted basement membrane and laminin gel in vitro. Half of the dissociated epiblast cells invade the gel substratum after one-day of culture, whereas the others attach to the gel but do not invade. It is expected that such heterogeneity in the behavior of the epiblast cells reflects some mechanism that sorts the cells into those that will ingress into the blastocoelic cavity and those that will remain in the epiblast layer. To test this hypothesis, we dissociated chick prestreak epiblast cells into single cells, cultured them on the laminin gel, and then stained them with anti-HNK-1 antibody. This antibody binds to an epitope present on half of the prestreak epiblast cells which are thought to differentiate into presumptive mesoendodermal cells. We found that 80% of the invasive epiblast cells were HNK-1-positive whereas 77% of the non-invasive cells were HNK-1 negative. In the case of invasive cells, the edges of the proteolytic holes made by the invasive cells were often stained. These results suggest that the cells expressing the HNK-1 carbohydrate chain are preferentially invasive, and this induces selective ingression of the carrier cells for mesoendodermal differentiation in vivo.
Mogi
K
K
Department of Biological Sciences, Faculty of Science, Kanagawa University, Hiratsuka city, Japan.
Toyoizumi
R
R
Takeuchi
S
S
D000818:Animals; D018959:CD57 Antigens / Q000096:biosynthesis*; D002465:Cell Movement; D002478:Cells, Cultured; D002642:Chick Embryo; D004707:Endoderm / Q000378:metabolism; D000939:Epitopes; D007797:Laminin / Q000378:metabolism; D008648:Mesoderm / Q000378:metabolism; D008858:Microscopy, Phase-Contrast; D013997:Time Factors
D018959:CD57 Antigens; D000939:Epitopes; D007797:Laminin