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Published June 1996 | public
Journal Article

Expression of the Avian α_7-Integrin in Developing Nervous System and Myotome

Abstract

Integrins are cell surface receptors for a variety of extracellular matrix molecules including fibronectin, laminin and collagens. Although their role in development is not completely understood, they are likely to have important functions in cell migration and axon guidance. To characterize the types of integrins expressed in the developing nervous system, we have used monoclonal antibodies against α_7- and α_v-integrin subunits to examine the distribution of these subunits in the early chick embryo. Low levels of α_7 immunoreactivity were first observed in the neural tube and developing myotome of stage 17 embryos (E2.5). Although low levels of α_7 expression were associated with most neuroepithelial cells, distinct α_7 immunoreactivity was first detected in the ventrolateral portions of the neural tube at a stage corresponding to the time when the first neurons differentiate. Its distribution pattern overlapped with that of commissural neurons in the developing spinal cord. α_7 was also prominently localized to the motor neurons and their axons emanating from the neural tube. In addition, α7 immunoreactivity was observed on a subpopulation of trunk neural crest cells migrating through the somitic sclerotome. At later stages, α_7 expression was observed in other nervous system structures such as the pigmented retinal epithelial cells. In addition to its distribution in the developing nervous system, α_7 immunoreactivity was associated with early myotomal cells shortly after myotome formation and its expression persisted throughout myotome development. In contrast to α_7, α_v-integrin had a limited distribution in the nervous system, being expressed only at low levels in the neural tube. However, α_v displayed prominent immunoreactivity in the myotome and in endothelial cells of the dorsal aorta. The results suggest that α_7-integrin is one of the prevalent integrin subunits on neurons and axons in the developing spinal cord.

Additional Information

© 1996 Published by Elsevier Science Ltd. Received 11 August 1995; revised 29 October 1995; accepted 29 October 1995. Available online 5 March 1999. We thank Patty Wang for excellent technical assistance. This work was supported by USPHS HD-15527 to MBF.

Additional details

Created:
August 22, 2023
Modified:
October 18, 2023