Skip to main content
. Author manuscript; available in PMC: 2013 Jan 15.
Published in final edited form as: Dev Biol. 2011 Oct 26;361(2):232–244. doi: 10.1016/j.ydbio.2011.10.024

Fig. 8. Individual MG have distinct positions and morphologies.

Fig. 8

Individual AMG or PMG from argos-G1.1-Gal4 UAS-tau-GFP embryos in sagittal view. Red and white circles show the AC and PC. Anterior is to the left and dorsal is up. (A–C′) The elaboration of projections and cell shape (anti-GFP) for individual AMG during stage 16 is shown for AMG in the: (A,A′) DA region, (B,B′) DM region, and (C, C′) VM region. Anti-Sim (blue) staining reveals MG nuclei in (A–C), and MG and a subset of midline neurons in (G–L). MAb BP102 axonal staining shows the location of the commissures. (A,A′) Sim+ AMG nucleus resides above the AC in the DA region, and GFP staining reveals that its cytoplasm covers the anterior face of the AC and portions of the dorsal and ventral faces. Projections (white arrow) are present only in the AC. (B,B′) An AMG nucleus resides above and between the AC and PC in the DM region. Cytoplasm covers portions of the dorsal face of the AC and PC and extends between the commissures covering portions of the ventral face of both the AC and PC. Projections enter both the AC and PC with some extending the length of the PC (white arrow). (C,C′) The nucleus of an AMG resides in the VM region, under and between the AC and PC. The cytoplasm covers portions of the ventral faces of the AC and PC, extends up in between the AC and PC, and covers portions of the dorsal faces of the AC and PC. Projections are found in both commissures with some extending the length of the PC (white arrow). (D) Schematic interpretation of individual AMG morphology at stages 16 and 17 in the DA, DM, and VM regions based on images from 25 AMG. Together, AMG cover the entire surface of both commissures. (E,F) At stage 12/3, individual (E) AMG and (F) PMG have long trailing processes (white arrowheads) as they migrate internally. The single commissure is shown by anti-BP102 staining (white arrow). Dotted lines in E demarcate the boundaries with GFP-stained non-midline cells. (G–L) At stage 14, there are distinct morphologies of (G–J) AMG and (K,L) PMG. (G,H) AMG that are in contact with the AC (white arrowhead) stain strongly for GFP, have an elongated cuboidal shape, and show small projections into the commissures (white arrows). (I) AMG at a distance from the commissure stain weakly with GFP and are more rounded (white arrowheads). (J) An AMG (white arrowhead) has an extended comet-like morphology that does not contact the epidermis. (K) At stage 14, a PMG (white arrowhead) contacting the PC has an elongated shape and retains a trailing process. (L) In contrast, a PMG that does not touch the PC (white arrowhead) is rounded and resides posterior to a PMG (orange asterisk) that does contact the PC. No PMG were identified at any stage that ensheathed or sent projections into the commissures.