Collagen IV, laminin and fibronectin expression in human fetal female gonads during early development W7.3. (A,B) Collagen IV (green) expression identified the mesonepheric glomerulus, mesonephric and paramesonepheric ducts, and is present in the gonad. (C,D) laminin (green) (C), and fibronectin (green) (D) expression during early development of female gonads (W7.3). Germ cells (red) were identified by the early marker OCT4 (nuclear) and late marker VASA (cytoplasmic). The same secondary antibody was used to detect OCT4 and VASA, because the two proteins localize to different cellular compartments (nucleus and cytoplasm, respectively) and their expression can therefore be clearly distinguished. The white asterisks marked individual germ cells expressing collagen IV and laminin. Scalebars are 100 μm.