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Fig. 4.
The fibronectin (FN) matrix is defective next to cells with compromisedaqp3bexpression within the DMZ. Gastrula embryos (stage 10.5) that had been co-injected with MOs and membrane-bound mem-EGFP tracer RNA (green) were hemisected sagittally through the dorsal blastopore lip, stained with FN antibodies (red), and evaluated by confocal microscopy. (A) In a control MO1-injected gastrula embryo, the FN matrix extended along the inner surface of the blastocoel roof and into the dorsal and ventral marginal zones. (B-H) Control MO-injected embryos had an uninterrupted FN matrix. The dashed box in the lower magnification image (B) indicates the area shown in (C, F) from a different optical plane. Continuous FN matrix was also present in embryos injected with control MO2 (D, G) and both control MOs (E, H). The green channel (mem-EGFP) was omitted in the lower panels to clearly show the extent of the FN matrix (red), which was continuous between non-involuted ectoderm and involuted mesendoderm. (I-O) aqp3b morphants showed interruption of the FN matrix wherever aqp3b MOs were present (marked by green mem-EGFP tracer). The dashed box in (I) shows an equivalent area as in (J, M). In the area sandwiched between ectoderm and mesendoderm, the fibrillar FN matrix is highly disrupted by the presence of aqp3b MO1 (I, J, M), aqp3b MO2 (K, N), and synergistically in embryos injected with lower amounts of both aqp3b MOs (L, O). DMZ, dorsal marginal zone; VMZ, ventral marginal zone; BCR, blastocoel roof; DLB, dorsal blastopore lip; e, ectoderm; me, mesendoderm; bc, blastocoel cavity; the dotted lines demarcate the floor of the blastocoel. Scale bars: 50 um. |
