title: Antisense inhibition of R-cognin expression modulates differentiation of retinal neurons in vitro.
abstract: OBJECTIVE
  Retina cognin (R-cognin) is a 50 kDa membrane-associated polypeptide expressed during retinogenesis where it is involved in mediating tissue-specific cell-cell interactions. In addition to its intercellular role in aggregation, R-cognin may act as a cell surface signaling molecule. An antisense oligonucleotide was used to inhibit R-cognin expression and to investigate the effects of this inhibition on subsequent neuronal differentiation.
  
  
  METHODS
  Cultures of retina cells were prepared from 6 day (E6) and 8 day (E8) chicken embryos and were incubated with a deoxyoligonucleotide complimentary to 20 bases of the sequence encoding R-cognin or random oligonucleotides. The levels of choline acetyltransferase (ChAT) and glutamic acid decarboxylase (GAD), markers of cholinergic and GABAergic differentiation, respectively, were detected by Western blots on protein extracts from treated cultures.
  
  
  RESULTS
  The antisense treatment inhibited ChAT levels at E6 and GAD levels at E8. The treatment resulted in no decrease in the level of the enzyme glyceraldehyde 3-phosphate dehydrogenase. A random oligonucleotide did not affect the levels of any of the proteins.
  
  
  CONCLUSIONS
  These results confirm the cell recognition role of R-cognin and suggest that it is important in intracellular signaling cascades necessary for normal retina development.
authors.affiliation: Department of Biology, Boston University, Boston, MA 02215, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Phillips
authors.forename: D R
authors.initials: DR
authors.lastname: Tolan
authors.forename: R E
authors.initials: RE
authors.lastname: Hausman
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D002642:Chick Embryo; D002795:Choline O-Acetyltransferase / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005968:Glutamate Decarboxylase / Q000378:metabolism*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism; D008565:Membrane Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D010446:Peptide Fragments / Q000378:metabolism; D016548:Prosencephalon / Q000187:drug effects / Q000378:metabolism; D012160:Retina / Q000187:drug effects / Q000378:metabolism*; D013477:Superior Colliculi / Q000187:drug effects / Q000378:metabolism; D013997:Time Factors
chemical_list: D008565:Membrane Proteins; D016376:Oligonucleotides, Antisense; D010446:Peptide Fragments; C026097:cognin; C068142:glyceraldehyde 3-phosphate dehydrogenase (304-313); D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D002795:Choline O-Acetyltransferase; D005968:Glutamate Decarboxylase