Connexin43 interacts with NOV: a possible mechanism for negative regulation of cell growth in choriocarcinoma cells.
The gap junction protein connexin43 (Cx43) is thought to be involved in growth control in several tissues. Using the doxycycline inducible tet-on system, we generated human malignant trophoblast Jeg3 cells transfected with either Cx40, Cx43, or C-terminal truncated Cx43 (trCx43). Cx43, but not Cx40 or trCx43, displayed a reduced cell growth of Jeg3 cells in vitro and tumor growth in nude mice, suggesting a role of the C terminus of Cx43 in growth regulation. Using gene array analysis, the growth regulator NOV (CCN3), a member of the CCN gene family, was found to be up-regulated only in the Cx43-transfected cells. Validation by reverse transcriptase-PCR confirmed an up-regulation of the NOV transcript exclusively upon Cx43 induction. In contrast to Cx40 or trCx43, induction of Cx43 led to a switch in localization of NOV from the nucleus to the cell membrane, where it is colocalized with Cx43. Coimmunoprecipitation showed a binding of NOV to the C terminus of Cx43 in vitro as well as in transfected cells. Jeg3 cells transfected only with NOV revealed that NOV itself acts as a growth regulator. We suggest that Cx43 is able to regulate cell growth via an up-regulation of NOV transcription, a change in localization of the NOV protein and a binding of NOV to the C terminus of Cx43.
Gellhaus
Alexandra
A
Institute of Anatomy and Cell Biology, University Hospital Essen, 55 Hufelandstrasse, 45122 Essen, Germany.
Dong
Xuesen
X
Propson
Sven
S
Maass
Karen
K
Klein-Hitpass
Ludger
L
Kibschull
Mark
M
Traub
Otto
O
Willecke
Klaus
K
Perbal
Bernard
B
Lye
Stephen J
SJ
Winterhager
Elke
E
D000818:Animals; D015152:Blotting, Northern; D002455:Cell Division; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D055513:Connective Tissue Growth Factor; D018031:Connexin 43 / Q000378:metabolism*; D017630:Connexins / Q000378:metabolism; D006801:Humans; D017874:Immediate-Early Proteins / Q000378:metabolism*; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008856:Microscopy, Fluorescence; D009368:Neoplasm Transplantation; D055514:Nephroblastoma Overexpressed Protein; D020411:Oligonucleotide Array Sequence Analysis; D009841:Oligonucleotides / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014162:Transfection; D015854:Up-Regulation; D000097003:Gap Junction alpha-5 Protein
D055513:Connective Tissue Growth Factor; D018031:Connexin 43; D017630:Connexins; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D055514:Nephroblastoma Overexpressed Protein; D009841:Oligonucleotides; D020033:Protein Isoforms; D012333:RNA, Messenger; D000097003:Gap Junction alpha-5 Protein; C526317:CCN2 protein, human; C526318:CCN2 protein, mouse; C526319:CCN3 protein, human; C526320:Ccn3 protein, mouse