Fig. 4

a Histological view of a mouse uterus stained with H&E depicting the different layers making up the uterine wall. b Immunohistochemical stains of mouse uteri in proestrus/estrus (P/E), metestrus (M) or diestrus (D) stained for Fn (green) and relaxed Fn using FnBPA5 (pink). While there is a constant and homogenous expression of Fn, there is a distinctly higher abundance of relaxed Fn (FnBPA5) in the myometrium during proestrus/estrus (P/E). All images are shown in Additional file 1: Figures S4a-c. c Quantitative analysis of the fluorescent signal in the myometrium of uteri in different cycle stages. αSMA is a marker for myofibroblasts, which are the main producers of Fn in tissues. While there is no change in αSMA and Fn signal in the myometrium along the estrous cycle, relaxed Fn (FnBPA5) is significantly more abundant during proestrus/estrus. Statistical analysis was conducted using one-way ANOVA with Tukey’s multiple comparison post hoc test (*p < 0.05, **p < 0.01) Raw data is summarized in Additional file 1: Table S3