Expression of the HNK-1 epitope is unaltered among early chick epiblast cells despite behavioral transformation by inducing factors in vitro.
Dissociated epiblast cells from pre-streak chick blastoderms have been exposed, in short-term culture on a fibronectin (FN) substratum, to recombinant mammalian activin and to mammalian basic fibroblast growth factor (bFGF). Such cultures have also been made on this substratum pre-conditioned by culture of a transfected cell line expressing the mammalian Wnt-1 gene. The former two factors induce changes of FN adhesiveness and other behavior, such that the cultures after 6 h resemble cultures newly set up from the young primitive streak or substreak hypoblast region of similarly aged blastoderms that have developed onward across the intervening period (see Cooke and Wong, Development 111: 197-212, 1991 for related results). Over 95% of cells are potentially responsive, and with relatively high concentration of activin there is also production of nodular structures due to strong cell-cell adhesion, as in cultures from Hensen's node or the anterior streak. Pre-conditioning of the substratum by transfected Wnt-1-expressing cells does not appear specifically to alter behavior in such epiblast cultures, though these experimental cells, and not control-transfected ones, produce striking alterations of chick development in other experiments (Cooke et al., in preparation). Up to 20% of cells in control cultures from central or 'marginal zone' pre-streak epiblast express the HNK-1 epitope, while up to 60% of cultured early streak cells cleaned of hypoblast do so.(ABSTRACT TRUNCATED AT 250 WORDS)
Cooke
J
J
National Institute for Medical Research, London, United Kingdom.
D028341:Activins; D000818:Animals; D001756:Blastoderm / Q000378:metabolism*; D002478:Cells, Cultured; D002642:Chick Embryo; D000939:Epitopes / Q000096:biosynthesis*; D016222:Fibroblast Growth Factor 2 / Q000502:physiology; D005353:Fibronectins / Q000378:metabolism; D006133:Growth Substances / Q000502:physiology*; D007265:Inhibins / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014170:Transformation, Genetic; D051153:Wnt Proteins; D051155:Wnt1 Protein; D029961:Zebrafish Proteins
D000939:Epitopes; D005353:Fibronectins; D006133:Growth Substances; D011518:Proto-Oncogene Proteins; D051153:Wnt Proteins; D051155:Wnt1 Protein; D029961:Zebrafish Proteins; D016222:Fibroblast Growth Factor 2; D028341:Activins; D007265:Inhibins