Fig. 6

PHR does not control the morphology of MBP- and GFAP-positive glial cells. Time-lapse imaging over 9 h of regrowing Mauthner axons labeled by Tg(hspGFF62a) and Tg(UAS:gap43_1-20-RFP). Myelinating oligodendrocytes are transgenically labeled in Tg(MBP:EGFP-CAAX) in (a–j) and GFAP-positive glial cells are labeled in TgBAC(GFAP:GFAP-GFP) in (k–n). In wild type (a–e) and phr mutant (f–j), laser-mediated axon transection caused minor damage (fragmentation and rounding) of myelinating oligodendrocytes (white stars) around the transection site (yellow arrowheads), compared to the pretransection images (e, j). Except minor damage, myelinating oligodendrocytes neither displayed obvious morphological changes nor interfered with the transection site or formed any obvious scar tissue in any of the larvae (n = 4 wild type and n = 4 phr mutants). We did not observe any differences in the morphology of MBP-positive glial cells between wild type and phr mutant larvae before or after transection. Note also the rostrally extending axonal processes in wild type (retracting over time; shorter in (d) than in (c), marked by white arrows), and in the phr mutant (longer in (i) than in (h), marked by white arrows). k–n Laser-mediated axon transection also caused minor damage to GFAP-positive glial cells in all larvae analyzed (n = 4 wild type, n = 4 phr mutants). Except minor damage, GFAP-positive glial cells neither displayed obvious morphological changes nor interfered with the transection site or formed any obvious scar tissue in any of the larvae (n = 4 wild type and n = 4 phr mutants). We did not observe any differences in the morphology of GFAP-positive glial cells between wild type and phr mutant axons before or after transection. Scale bar in (a) is 20 μm