Retinoic acid enhances connexin43 expression at the post-transcriptional level in rat liver epithelial cells.
The mechanism by which all-trans retinoic acid (RA) stimulates gap junctional intercellular communication (GJIC) in the rat liver epithelial cell line. IAR203, was investigated. When RA, at 0.1 microM for 24-48 h, enhanced the dye transfer in IAR203 cells (x 1.4), it increased the amount of connexin43 (Cx43) in the cell-cell contact regions of the plasma membrane, as evidenced by analysis by Western blot and by immunofluorescence. It had no effect on the level of Cx43 mRNA. Freeze-fracture analysis of the size of gap junctions revealed an increase of the proportion of small gap junctions in RA-treated cells. We conclude that, in IAR203 cells, RA stimulates GJIC by acting at the post-transcriptional level of Cx43 regulation. The possibility that RA acts indirectly on the regulation of Cx43 expression, and increases the half-life of Cx43 by inducing adhesion molecules is discussed.
Bex
V
V
Institut National de la Recherche Agronomique, Laboratoire de Nutrition et Sécurité Alimentaire, Jouy-en-Josas, France.
Mercier
T
T
Chaumontet
C
C
Gaillard-Sanchez
I
I
Flechon
B
B
Mazet
F
F
Traub
O
O
Martel
P
P
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D015153:Blotting, Western; D002460:Cell Line; D004396:Coloring Agents; D018031:Connexin 43 / Q000096:biosynthesis*; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D005614:Freeze Fracturing; D017629:Gap Junctions / Q000187:drug effects; D006207:Half-Life; D008099:Liver / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D014176:Protein Biosynthesis / Q000187:drug effects; D011499:Protein Processing, Post-Translational / Q000187:drug effects*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D014212:Tretinoin / Q000494:pharmacology*
D004396:Coloring Agents; D018031:Connexin 43; D012333:RNA, Messenger; D014212:Tretinoin