Proceeding of Veterinary and Animal Science Days 2015, 15th- 17th  July,  Milan, Italy 

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CORRESPONDING AUTHOR 

Valentina Lodde 

 valentina.lodde@unimi.it 

 

 

The present studies were aimed to assess Progesterone Receptor Membrane Component-1 (PGRMC1) role in 
regulating bovine granulosa cells (bGC) mitosis. First, we performed immunofluorescence studies on in vitro 
cultured bGC collected from antral follicles, which showed that PGRMC1 localizes to the spindle apparatus in 
mitotic cells. Then, to evaluate PGRMC1 effect on cell proliferation we silenced its expression with RNA 
interference technique (RNAi). Quantitative RT-PCR and immunoblotting confirmed down-regulation of PGRMC1 
expression, when compared to CTRL-RNAi treated bGC (p<0.05). After 72h of culture, PGRMC1 silencing 
determined a lower growth rate (p<0.05) and a higher percentage of cells arrested at G2/M phase as assessed by 
flowcytometry (p<0.05). Accordingly, live imaging studies revealed more aberrant mitosis and a delayed M-phase 
in PGRMC1-RNAi treated cells compared to CTRL-RNAi group (p<0.05). These data confirmed that PGRMC1 is 
directly involved in bGC mitosis and ongoing preliminary studies are aimed to elucidate its putative mechanisms 
of action. Since PGRMC1 is a membrane protein, we hypothesize its possible involvement in vesicular trafficking 
and endocytosis, which is in turn an important process to assure proper cell division. To assess this hypothesis, 
we have preliminarily conducted immunofluorescence and in situ proximity ligation assay experiments that 
showed PGRMC1 co-localization and direct interaction with clathrin. This is important since clathrin is an essential 
protein for both endosomes formation, and cell division acting directly on the spindle apparatus. Thus our studies 
set the stage for analysis aimed to further characterize PGRMC1’s mechanism of action in mitotic cells. 

Funding: FP7-PEOPLE-2011-CIG-303640; Fondo Ricerca Giovani Ricercatori-15-6-3027000-54. 

       REFERENCES  
Lodde V, Peluso JJ. A novel role for progesterone and progesterone receptor membrane component 1 in regulating 
spindle microtubule stability during rat and human ovarian cell mitosis. Biology of reproduction 2011; 84:715-722. 

  
Royle SJ, Bright NA, Lagnado L. Clathrin is required for the function of the mitotic spindle. Nature 2005; 434:1152-

1157.  

 

 

Progesterone Receptor Membrane 

Component-1 in cell division: its role in 

bovine granulosa cells mitosis. 

L. Terzaghi, A. M. Luciano, V. Lodde 

Reproductive and Developmental Biology Laboratory - Department of 

Health, Animal Science and Food Safety, Università degli Studi di Milano, Via 

Celoria 10, 20133 Milan, Italy