Development, Vol 122, Issue 8 2539-2554, Copyright © 1996 by Company of Biologists

JOURNAL ARTICLES

Integrin alpha 6 expression is required for early nervous system development in Xenopus laevis

TE Lallier, CA Whittaker and DW DeSimone
Department of Cell Biology, University of Virginia, Charlottesville 22908, USA.

The integrin alpha 6 subunit pairs with both the beta 1 and beta 4 subunits to form a subfamily of laminin receptors. Here we report the cDNA cloning and primary sequence for the Xenopus homologue of the mammalian integrin alpha 6 subunit. We present data demonstrating the spatial and temporal expression of alpha 6 mRNA and protein during early development. Initially, alpha 6 transcripts are expressed in the dorsal ectoderm and future neural plate at the end of gastrulation. Later in development, alpha 6 mRNAs are expressed in a variety of neural derivatives, including the developing sensory placodes (otic and olfactory) and commissural neurons within the neural tube. Integrin alpha 6 is also expressed in the elongating pronephric duct as well as a subset of the rhombencephalic neural crest, which will form the Schwann cells lining several cranial nerves (VII, VIII and X). In vivo expression of an alpha 6 antisense transcript in the animal hemisphere leads to a reduction in alpha 6 protein expression, a loss of adhesion to laminin, and severe defects in normal development. In 35% of cases, reduced levels of alpha 6 expression result in embryos that complete gastrulation normally but arrest at neurulation prior to the formation of the neural plate. In an additional 22% of cases, embryos develop with severe axial defects, including complete loss of head or tail structures. In contrast, overexpression of the alpha 6 subunit by injection of full-length mRNA has no apparent effect on embryonic development. Co-injection of antisense and sense plasmid constructs results in a partial rescue of the antisense-generated phenotypes. These data indicate that the integrin alpha 6 subunit is critical for the early development of the nervous system in amphibians.

This article has been cited by other articles:

				A. R. Morris, J. Drawbridge, and M. S. Steinberg Axolotl pronephric duct migration requires an epidermally derived, laminin 1-containing extracellular matrix and the integrin receptor {alpha}6{beta}1 Development, December 1, 2003; 130(23): 5601 - 5608. [Abstract] [Full Text] [PDF]

				B. Hoang and A. Chiba Genetic Analysis on the Role of Integrin during Axon Guidance in Drosophila J. Neurosci., October 1, 1998; 18(19): 7847 - 7855. [Abstract] [Full Text] [PDF]

				Z. Zhang and D. S. Galileo Retroviral Transfer of Antisense Integrin alpha 6 or alpha 8 Sequences Results in Laminar Redistribution or Clonal Cell Death in Developing Brain J. Neurosci., September 1, 1998; 18(17): 6928 - 6938. [Abstract] [Full Text] [PDF]

				T. Jacques, J. Relvas, S Nishimura, R Pytela, G. Edwards, C. Streuli, and C ffrench-Constant Neural precursor cell chain migration and division are regulated through different beta1 integrins Development, January 8, 1998; 125(16): 3167 - 3177. [Abstract] [PDF]