Astrocytes and neurons express the tight junction-specific protein occludin in vitro.
The expression of occludin, an integral plasma membrane protein specifically located at tight junctions, was studied in various epithelial and nonepithelial tissues by means of RT-PCR, Western blotting, and immunofluorescent staining. Besides detection in epithelial and endothelial tissue, expression of occludin was found in primary and secondary cultures of neurons and astrocytes. Differentiation of astrocytes in vitro led to a marked decrease in occludin expression. Extractability of occludin from plasma membranes differed considerably between epithelial and nonepithelial cells. Following treatment with Triton X-100, occludin was completely extracted from astrocytic membranes but not from membranes derived from MDCK cells, suggesting a difference in the cytoplasmic and/or plasma membrane anchoring of occludin between these cell types.
Institute of Molecular Biology, Austrian Academy of Sciences, Salzburg, 5020, Austria. hcbauer@imb.oeaw.ac.at
H
H
Bauer
W
W
Stelzhammer
R
R
Fuchs
T M
TM
Weiger
C
C
Danninger
G
G
Probst
I A
IA
Krizbai
D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015153:Blotting, Western; D001921:Brain / Q000166:cytology / Q000196:embryology / Q000254:growth & development; D002454:Cell Differentiation; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D004285:Dogs; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D062793:Occludin; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012995:Solubility; D019108:Tight Junctions / Q000187:drug effects / Q000378:metabolism*
D008565:Membrane Proteins; D062793:Occludin; C568986:Ocln protein, mouse