Inx3 protein distribution in amnioserosa cells of an inx2 null mutant embryo.
The image shows a section of the surface of an 8-10 hour old inx2 null mutant embryo during dorsal closure. Leading edge (LE) cells of the epidermis (Ep) are extending over the large cells of the amnioserosa (As). In wild type amnioserosa cells Inx3 protein is detected as highly fluorescent linear puncta at the cell edge. This embryo has the genotype inx2F43/Y and produces no Inx2 protein. Consequently, Inx3 protein fails to form its characteristic large plaques, although it does form smaller punctae that are mostly localized at, or near, the cell periphery (arrowheads). They could therefore form functional gap junction channels or hemichannels in the plasma membrane despite their abnormal morphology. This observation supports previous reports from others that normal Inx3 protein distribution requires the presence of Inx2 ( Lehmann et al. 2006). Lehmann also reports that Inx3 protein accumulates as a cytoplasmic "cloud" around the nucleus in the absence of Inx2. There could be evidence of this in the image above ...or it could just be background staining that is not normally seen because, in this case, the microscope gain had to be increased significantly to view the diffuse Inx3 staining ...or this could just be a crappy prep.