PGCs and their surrounding cells in the germinal crescent express integrin beta 1 subunit protein on their cell surfaces. Whole-mount immunofluorescence for fibronectin and laminin receptors (integrin beta 1 subunit, abJG-22) and PGC-specific Dazl at two separate locations within an HH4 [Tg(hUbC:Membrane-eGFP)] quail embryo germinal crescent. (A) Central germinal crescent (see panel C for location). Left to right: Integrin beta 1 subunit (Itgb1, abJG-22, red), Dazl (PGC marker, green), membrane-GFP (blue), Itgb1 and membrane-GFP merge, Itgb1, membrane-GFP, Dazl merge (bounding box shown at higher magnification in E). White arrows indicate one PGC imaged in cross section with a clearly defined perimeter of Itgb1. 20x 0.8x zoom. (B) Lateral germinal crescent (see panel C for location). Left to right: Integrin beta 1 subunit (Itgb1, abJG-22, red), Dazl (PGC marker, green), membrane-GFP (blue), Itgb1 and membrane-GFP merge, Itgb1, membrane-GFP, DAZL merge (bounding box shown at higher magnification in D). White arrows indicate one PGC with a clearly defined perimeter of Itgb1 that was imaged at an oblique angle. 20x 1.0x zoom. (C) Tiled 10x confocal Z stack maximum intensity projections of the whole-mount HH4 embryo. Bounding boxes indicate location of images in (A,B). Itgb1 (red), Dazl (green). Scale bar C = 500μm. (D,E) Images are digital zooms of bounding boxes in (B,A) Merge. White arrows in (D,E) highlight particular PGCs with integrin beta 1 subunit receptor labeled puncta on the cell surface which was imaged in oblique (D) or in cross-section (E) by the confocal optical slice. Scale bar A, B, D, E = 25 μm.