title: Connexin43 interacts with NOV: a possible mechanism for negative regulation of cell growth in choriocarcinoma cells.
abstract: 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.
authors.affiliation: Institute of Anatomy and Cell Biology, University Hospital Essen, 55 Hufelandstrasse, 45122 Essen, Germany.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Gellhaus
authors.forename: Xuesen
authors.initials: X
authors.lastname: Dong
authors.forename: Sven
authors.initials: S
authors.lastname: Propson
authors.forename: Karen
authors.initials: K
authors.lastname: Maass
authors.forename: Ludger
authors.initials: L
authors.lastname: Klein-Hitpass
authors.forename: Mark
authors.initials: M
authors.lastname: Kibschull
authors.forename: Otto
authors.initials: O
authors.lastname: Traub
authors.forename: Klaus
authors.initials: K
authors.lastname: Willecke
authors.forename: Bernard
authors.initials: B
authors.lastname: Perbal
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Lye
authors.forename: Elke
authors.initials: E
authors.lastname: Winterhager
mesh_terms: 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
chemical_list: 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