Immunlocalisation of laminin α4 and α5. Laminin α4 (a, a’ counterstained with DAPI; follicles marked with stars) are not localised to structures of the mouse ovary but to the vasculature in mouse heart (c) and skeletal muscle (c’). Laminin α5 (b, b’ counterstained with DAPI; follicles marked with stars) is not detectable in mouse ovary, but in the vasculature (stars) and in the basal lamina of the tubule in mouse kidney (d, G glomerulus). Bar 100 μm (a–b’, d, 50 μm (c, c’)

Co-localisation of matrix components (green) with the endothelial cell marker PECAM-1 (red) in capillary sub-endothelial basal lamina in corpora lutea. a, b Perlecan. c Laminin γ1. d Collagen type XVIII. e Nidogen 1. f Nidogen 2. Nuclei are counterstained blue with DAPI (f). Bar 100 μm (a, c, e, f), 50 μm (b, d)

Immunlocalisation of matrix components in mouse ovaries. a–c Perlecan (green) is localised to the basal lamina of primordial, primary, preantral, antral (a, b) and atretic follicles (c) and in focimatrix (arrows). Laminin α2 (red) can be found in the basal lamina of some preantral, antral (a, b) and atretic follicles (c). Perlecan is also localised to the sub-endothelial basal lamina of blood vessels in the stroma (star), in the theca (rhombus) and corpora lutea (triangles) and to the basal lamina of smooth muscle cells of arterioles. d–f Laminin γ1 (green) is co-localised (yellow) with laminin α1 (red) in the basal lamina of all stages of follicular development (d, e), in atretic (f) and in regressing (open square) follicles. Laminin γ1 is also localised to the sub-endothelial basal lamina of blood vessels in the stroma, in the theca (rhombus) and corpora lutea (triangles) and to the basal lamina of smooth muscle cells of arterioles (stars). Laminin α1 is weakly detectable in the corpora lutea. Both laminins are found in the focimatrix (arrows). g–i Collagen type XVIII (green) is localised to the basal lamina of primordial, primary and some preantral follicles but not in antral follicles. In comparison, laminin β1 (red) is localised in the basal lamina of all follicular stages. Both matrix components are found in the focimatrix (arrows). The sub-endothelial basal lamina in stroma and corpora lutea (triangles) and the basal lamina of smooth muscle cells of arterioles contain collagen XVIII (stars) and some also laminin β1. Nuclei are counterstained blue with DAPI (i). j–l Nidogen 1 (green) is expressed in the basal lamina of all follicular stages and in the sub-endothelial basal lamina of blood vessels in the stroma (stars), in the theca (rhombus) and corpora lutea (triangle). It is also detectable in the basal lamina of atretic follicle (l) and in the focimatrix (arrows). m–o Nidogen 2 (green) is co-localised with laminin β1 (red) in the basal lamina of all follicular stages (m, n) and atretic follicles (o). Both markers can be found in the sub-endothelial basal lamina of blood vessels in the stroma (stars), in the theca (rhombus) and corpora lutea (triangles) and in the basal lamina of smooth muscle cells of arterioles. Nuclei are counterstained blue with DAPI (o). Bars 100 μm (a, b, d–h, j–n), 50 μm (c, i, o)

Composition of focimatrix (arrows) in mouse ovaries. a Aggregates and fibres of perlecan (green) in the granulosa layer. The focimatrix does not contain laminin α2 (red). b Higher magnification of the follicle marked with a star in a. c Co-localisation (yellow) of laminin γ1 (green) and laminin α1 (red) in focimatrix. d–f Laminin β1 (red) co-localised (yellow) in focimatrix with collagen type XVIII (green) in d, with nidogen 1 (green) in e and with nidogen 2 (green) in f. Bar 50 μm (a, c, d), 25 μm (b, e, f)