title: Characterization of the integrin alpha 8 subunit: a new integrin beta 1-associated subunit, which is prominently expressed on axons and on cells in contact with basal laminae in chick embryos.
abstract: In this article, we describe the primary structure, the biochemical characterization and the tissue distribution of a novel integrin alpha subunit, named alpha 8. This subunit associates with the integrin beta 1 subunit to form alpha 8 beta 1 heterodimers. By sequence analysis, alpha 8 is more closely related to the alpha 5 and alpha v subunits than to other characterized integrin alpha subunits, but is clearly distinct from each of these. The alpha 8 subunit is expressed at moderate levels in several epithelial cells where its localization adjacent to basal laminae suggests that alpha 8-containing heterodimers interact with at least one extracellular matrix constituent. In embryos, the highest levels of alpha 8 protein expression are seen in the nervous system where alpha 8 is strongly expressed by several classes of projection neurons. The alpha 8 subunit is concentrated in axon tracts, including major projections in the spinal cord, optic system and auditory system. This tissue specific expression and cellular localization suggest that alpha 8-containing integrin receptors might promote axon outgrowth in the embryonic nervous system.
authors.affiliation: Department of Physiology, University of California San Francisco, 94143.
authors.forename: B
authors.initials: B
authors.lastname: Bossy
authors.forename: E
authors.initials: E
authors.lastname: Bossy-Wetzel
authors.forename: L F
authors.initials: LF
authors.lastname: Reichardt
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001369:Axons / Q000737:chemistry*; D001483:Base Sequence; D001485:Basement Membrane / Q000737:chemistry*; D015152:Blotting, Northern; D002642:Chick Embryo; D003001:Cloning, Molecular; D004247:DNA; D004064:Digestive System / Q000737:chemistry; D005895:Gizzard, Avian / Q000737:chemistry; D007150:Immunohistochemistry; D016023:Integrins / Q000032:analysis / Q000235:genetics*; D008969:Molecular Sequence Data; D009900:Optic Nerve / Q000737:chemistry; D012313:RNA / Q000032:analysis; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D012867:Skin / Q000737:chemistry; D014566:Urogenital System / Q000737:chemistry
chemical_list: D016023:Integrins; D012313:RNA; D004247:DNA