Expression of CD44 during early development of the chick embryo

CD44, the major cell-surface receptor for hyaluronate, is expressed on many cell types to mediate different functions including cell activation, homin g and adhesion. The early pattern of CD44 expression was determined in the avian embryo by using a specific monoclonal antibody in whole-mount and tis sue sections. CD33, was first expressed on cephalic neural fold cells and l ater on by subpopulations of pre-and migraton, cranial neural crest cells. Trunk neural crest cells did not express CD44. At the 18-20 somite stage, C D44 expressing cells were also localized in the caudal region of the embryo , in the mesoderm of the remaining primitive streak and in the caudal ectod erm and above the secondary neural tube Juring the process of cavitation. I n addition, some hemopoietic cells present in the blood stream were also CD 44 positive. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.