Similar to the closely related GMMe cell line, the GMMs line was established via stable transfection of mink (Mustela vison) endometrial tissue using a plasmid vector encoding the SV40 large T antigen driven by the human beta-actin promoter. The cells were cotransfected with a second plasmid vector in order to impart neomycin resistance and were selected in medium containing G418.

Unlike GMMe cells, however, which exhibit epithelial morphology, GMMs cells display characteristics associated with cells of stromal origin. The fibroblast-like GMMs cells are positive for the intermediate filament protein vimentin and the enzyme alkaline phosphatase, but are negative for desmin and cytokeratin. The line has been experimentally utilized in coculture with mink embryos in obligate diapause to improve the duration and rate of embryo survival in vitro with a significant amount of success.

The term stroma generally refers to the supportive framework of an organ, gland, or other biological component. By definition the stroma is distinguished from the parenchyma, which is the essential, characteristic part of an organ or other structure. In the endometrial layer of the uterus, the stroma underlies a simple columnar epithelium and is very thick. Tubular uterine glands span the thickness of the supportive stroma and a complex of reticular fibers surrounds the stromal cells. Hormonal changes in the female body related to the menstrual cycle, however, periodically affect the stroma and the rest of the endometrium.

A culture of GMMs fibroblasts (featured in the digital image above) was labeled for the mitochondrial network with MitoTracker Red CMXRos, a derivative of X-rosamine. In addition, the culture was labeled for the cytoskeletal F-actin and DNA in the cell nucleus with Alexa Fluor 488 conjugated to phalloidin and Hoechst 33342, respectively. 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 Histones and Peroxisomes in GMMs Cells with Double Immunofluorescence - In a double immunofluorescence experiment, an adherent monolayer culture of mink endometrium fibroblast cells was fixed, permeabilized, blocked with 10-percent normal goat serum, and then treated with a cocktail of mouse anti-histone and rabbit anti-PMP 70 (peroxisomal membrane protein 70) primary antibodies followed by goat anti-mouse and anti-rabbit secondary antibodies (IgG) conjugated to BODIPY FL and Alexa Fluor 568, respectively. The filamentous actin network was counterstained with Alexa Fluor 350 conjugated to a phallotoxin, phalloidin.

Cultured Mink Uterus Fibroblasts Labeled with Alexa Fluor 350, BODIPY FL, and Alexa Fluor 568 - Nuclear histone proteins were targeted in the culture of mink endometrium fibroblast cells presented in this section with mouse anti-histone (pan) monoclonal antibodies, which were imaged with goat anti-mouse Fab fragments conjugated to BODIPY FL (labeling the nucleus). The specimen was simultaneously labeled for peroxisomes with Alexa Fluor 568 conjugated to goat secondary antibodies that target rabbit anti-PMP 70. Alexa Fluor 350 conjugated to phalloidin was utilized to counterstain the cytoskeletal F-actin network.