ATF2 expression in somatic and visceral motoneurons at E11.5 and E12.5.

(A–D) Fluorescence immunostaining for phosphorylated ATF2 (ATF2-PT71, red). (A'–D') Double immunofluorescence staining for phosphorylated ATF2 (red) and postmitotic marker Isl-1 (green). Phosphorylated ATF2 is robustly detected in E12.5 hypoglossal (h) and dorsal vagal (v) motoneurons (A, A'), in E12.5 abducens (abd) motoneurons (B, B', arrowheads) and in facial branchiomotor neurons (C, C') at E11.5. In addition phospho-ATF2 is also detected in C1 motoneurons of the spinal cord at E13.5 (D, D', arrowheads). Little or no expression of phosphorylated ATF2 is found in the surrounding cells or on the dorsal side of the brainstem at this stage. Bar: 100 µm. (E, E') E12.5 hypoglossal (h) and dorsal vagal (v) motoneurons express ATF2 as shown by immunostaining with ATF2-DBD antibody (red) and Isl-1 (green). r4, r5, r7, rhombomere, 4, 5, and 7.