Connexin 32 fused to the green fluorescent protein retains its ability to control the proliferation of thyroid cells.
Cell-to-cell exchanges of signaling molecules are thought to be involved in the control of cell proliferation. Connexins, which are encoded by a family of genes expressed in a cell type-specific manner, are considered as tumor suppressors. Thyroid epithelial cells co-express connexin 32 (Cx32) and connexin 43 (Cx43) that form distinct and delocalized gap junctions in vivo. The communication-deficient rat thyroid-derived cell lines, FRTL-5 and FRT, stably transfected with the Cx32 cDNA, have a reduced proliferation rate related to a prolonged G1 cell cycle phase. To determine whether Cx32-gap junctions exert the same regulatory role in vivo, we have undertaken a program of production of transgenic mice over-expressing Cx32 specifically in thyrocytes. To this purpose, we designed a vector in which the Cx32 cDNA was fused to the gene encoding the enhanced green fluorescent protein (EGFP) and placed under the control of a strong and thyroid-specific promoter, the thyroglobulin gene promoter (pTg). In stably transfected FRTL-5 cells, the Cx32/EGFP chimeric protein forms functional gap junction channels and induces the same proliferation slowdown as native Cx32. The pTg-Cx32/EGFP construct should thus allow us to obtain the thyroid-targeted over-expression of Cx32 in the mouse to investigate the involvement of Cx32-gap junctions in thyroid growth, functional activity and propensity to form tumors.
Flachon
V
V
Institut National de la Santé et de la Recherche Médicale, Unité 369, Faculté de Médecine Lyon-RTH Laennec, France.
Durand
C
C
Selmi-Ruby
S
S
Rousset
B
B
Munari-Silem
Y
Y
D000818:Animals; D002455:Cell Division / Q000502:physiology*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D018031:Connexin 43 / Q000378:metabolism; D017630:Connexins / Q000235:genetics / Q000378:metabolism*; D017629:Gap Junctions / Q000378:metabolism; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D011401:Promoter Regions, Genetic; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013961:Thyroid Gland / Q000166:cytology / Q000378:metabolism*; D000097002:Gap Junction beta-1 Protein
D018031:Connexin 43; D017630:Connexins; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D000097002:Gap Junction beta-1 Protein