title: Developmental expression of laminin beta 2 in rat retina. Further support for a role in rod morphogenesis.
abstract: OBJECTIVE
  The authors previously hypothesized that laminin beta 2 (S-laminin) plays a role in directing photoreceptor development. The aim of this study was to examine the temporal and spatial expression pattern of beta 2 laminins in rat retina to test this hypothesis.
  
  
  METHODS
  Retinas from Sprague-Dawley rats were harvested on embryonic days (E) 14, 16, and 21, as well as on postnatal days (P) 2, 5, and 10. Cryostat sections were probed with antibodies directed against beta 2 laminin, laminin-1 (alpha 1-beta 1-gamma 1), and von Willebrand factor.
  
  
  RESULTS
  At the onset of rod photoreceptor birth (E14), laminin beta 2 surrounds the cells of the retinal pigmented epithelium (RPE) and is present on the apical surface of the retinal neuroepithelium. At E16, laminin beta 2 persists on the apical surface of the neuroepithelium and the subjacent apical surface of the RPE. At birth, laminin beta 2 fills the matrix between the juxtaposed surfaces of the RPE and neuroepithelium; moreover, laminin beta 2 immunoreactivity penetrates the neural retina. Throughout postnatal development, laminin beta 2 immunoreactivity surrounds maturing inner and outer segments. Laminin beta 2 also is found in association with blood vessels in the neural retina itself, as well as with choroidal blood vessels; in both places, it is co-localized with an endothelial marker, von Willebrand factor, and laminin-1.
  
  
  CONCLUSIONS
  The spatial and temporal expression of laminin beta 2 is consistent with its hypothesized role in rod development. Laminin beta 2 is in a unique position to interact with mitotically active cells (in early retinal development), uncommitted progenitors (in late embryonic development), developing rods (in early postnatal development), and mature outer segments (throughout adulthood). Together with our earlier functional data, these data support our hypothesis that this molecule is an important component of the interphotoreceptor matrix.
authors.affiliation: Department of Biology, Boston College, Chestnut Hill, MA 02167, USA.
authors.forename: R T
authors.initials: RT
authors.lastname: Libby
authors.forename: D D
authors.initials: DD
authors.lastname: Hunter
authors.forename: W J
authors.initials: WJ
authors.lastname: Brunken
mesh_terms: D000818:Animals; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D018507:Gene Expression Regulation, Developmental; D007797:Laminin / Q000378:metabolism*; D009024:Morphogenesis; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000196:embryology* / Q000254:growth & development / Q000378:metabolism*; D017948:Retinal Rod Photoreceptor Cells / Q000196:embryology / Q000502:physiology*; D014841:von Willebrand Factor / Q000378:metabolism
chemical_list: D007797:Laminin; D014841:von Willebrand Factor; C058783:laminin beta2