Development, Vol 104, Issue 4 643-655, Copyright © 1988 by Company of Biologists

JOURNAL ARTICLES

Changes in the expression of the carbohydrate epitope HNK-1 associated with mesoderm induction in the chick embryo

DR Canning and CD Stern
Department of Human Anatomy, Oxford, UK.

We report that a monoclonal antibody, HNK-1, identifies specific regions and cell types during primitive streak formation in the chick blastoderm. Immunohistochemical studies show that the cells of the forming hypoblast are HNK-1 positive from the earliest time at which they can be identified. Some cells of the margin of the blastoderm are also positive. The mesoderm cells of the primitive streak stain strongly with the antibody from the time of their initial appearance. In the epiblast, some cells are positive and some negative at pre-primitive-streak stages, but as the primitive streak develops a gradient of staining intensity is seen within the upper layer, increasing towards the primitive streak. At later stages of development, the notochord and the mesenchyme of the headfold are positive, while the rest of the mesoderm (lateral plate) no longer expresses HNK-1 immunoreactivity. This antibody therefore reveals changes associated with mesodermal induction: before induction, it recognizes the 'inducing' tissue (the hypoblast) and reveals a mosaic pattern in the responding tissue (the epiblast); after primitive streak formation, the mesoderm of the primitive streak that results from the inductive interactions expresses the epitope strongly. Affinity purification of HNK-1-related proteins in various tissues was carried out, followed by SDS-PAGE to identify them. The hypoblast, mesoderm and epiblast of gastrulating chick embryos have some HNK-1-related proteins in common, while others are unique to specific tissues. Attempts have been made to identify these proteins using Western blots and antibodies known to recognize HNK-1-related molecules, but none of the antibodies used identify the bands unique to any of the tissues studied. We conclude that these proteins may be novel members of the HNK-1/L2 family, and that they may have a role in cell interactions during early development.

This article has been cited by other articles:

				K. L. Waldo, D. H. Kumiski, K. T. Wallis, H. A. Stadt, Mary. R. Hutson, D. H. Platt, and M. L. Kirby Conotruncal myocardium arises from a secondary heart field Development, August 15, 2001; 128(16): 3179 - 3188. [Abstract] [Full Text] [PDF]

				S. Liedtke, H. Geyer, M. Wuhrer, R. Geyer, G. Frank, R. Gerardy-Schahn, U. Zahringer, and M. Schachner Characterization of N-glycans from mouse brain neural cell adhesion molecule Glycobiology, May 1, 2001; 11(5): 373 - 384. [Abstract] [Full Text] [PDF]

				L Bally-Cuif and M Wassef Ectopic induction and reorganization of Wnt-1 expression in quail/chick chimeras Development, January 12, 1994; 120(12): 3379 - 3394. [Abstract] [PDF]

				Y Hatada and C. Stern A fate map of the epiblast of the early chick embryo Development, January 10, 1994; 120(10): 2879 - 2889. [Abstract] [PDF]