The GMMe cell line is an epithelial line that tests positive for the intermediate filament proteins cytokeratin and vimentin, but is negative for desmin. The line is also positive for the enzyme alkaline phosphatase. GMMe cells have been co-cultured with mink embryos in obligate diapause to improve in vitro embryo survival.

Initiation of the GMMe line entailed the stable transfection of endometrial tissue excised from the uterus of an adult mink (Mustela vison) utilizing a plasmid vector encoding simian virus 40 (SV40) large tumor antigen (T antigen) driven by the human beta-actin promoter. The cells were then cotransfected with another plasmid vector in order to provide them with neomycin resistance. Cell selection was carried out in medium containing G418, an aminoglycoside commonly used as a selective agent of transfected cells.

The wall of the uterus is composed of three layers, the innermost of which is the mucus membrane known as the endometrium. Uterine glands, blood vessels, and lymphatic spaces are interspersed throughout the endometrium, which physically differs both at various points in the periodic reproductive cycle and at different stages of a mammal's reproductive life. For instance, the endometrium matures at puberty, but cyclically thickens in preparation for fertilization. When fertilization does not occur, parts of the endometrial lining are broken down and shed from the body. Hormone secretion under the control of the ovaries is primarily responsible for such changes.

The proximity of intermediate filaments and the cytoskeletal filamentous actin network was visualized by treating the fixed and permeabilized culture of mink uterus endometrium epithelial cells presented above with mouse anti-vimentin primary antibodies followed by goat anti-mouse secondary antibodies (IgG) conjugated to Texas Red-X. F-actin was subsequently labeled with Oregon Green 488 conjugated to phalloidin, and the nuclei were counterstained with Hoechst 33258. Images were recorded in grayscale with a 12-bit digital camera coupled to either a Nikon E-600 or Eclipse 80i microscope equipped with bandpass emission fluorescence filter optical blocks. During the processing stage, individual image channels were pseudocolored with RGB values corresponding to each of the fluorophore emission spectral profiles.

Targeting Vimentin in Mink Uterus Epithelial Cells with Immunofluorescence - Cultured GMMe cells were immunofluorescently labeled with primary anti-vimentin (an intermediate filament protein) mouse monoclonal antibodies followed by goat anti-mouse Fab fragments conjugated to Marina Blue. Alexa Fluor 594 conjugated to phalloidin (cytoskeletal F-actin network) and SYTOX Green (nuclei) were also used to stain the epithelial cell culture.

GMMe Cells Triple Labeled with MitoTracker Red CMXRos, Alexa Fluor 488, and Hoechst 33258 - The culture of mink endometrium epithelial cells presented in this section was labeled for mitochondria and the cytoskeletal filamentous actin network with MitoTracker Red CMXRos and Alexa Fluor 488 conjugated to phalloidin, respectively. In addition, cell nuclei were targeted with the nucleic acid stain Hoechst 33258.