Fig. 3. Stable microtubule populations are specifically disrupted when MURF-2 levels are knocked down in cardiac myocytes. (A) Day 3 cardiac myocytes were treated with control oligos (a-e) or MURF-2 antisense oligos (f-j) and incubated for 48 hours before fixation. MURF-2 staining was detected in control myocytes (a) but was nearly undetectable in antisense-treated myocytes (f). Staining for -tubulin appeared in a complex, radial web-like array in control myocytes (b), but appeared somewhat sparser in MURF-2 antisense treated cells (g). Strikingly, staining for Glu-tubulin appeared dim in antisense-treated myocytes (h), but bright and filamentous in control cells (c). Staining for Ac-tubulin also appeared dimmer in MURF-2 antisense treated myocytes compared to control cells (d,i). Finally, staining for the dynamic Tyr-MT populations did not appear to differ between control (e) and MURF-2 antisense treated cells (j). (B) Human GFP-MURF-2 expression rescues Glu-MTs in antisense-treated chick myocytes. Chick cardiac myocytes co-transfected with MURF-2 antisense oligos and human GFP-MURF-2 also were stained for Glu-tubulin. Myocytes expressing GFP-hMURF-2 (k), often detected in aggregates in the cytoplasm, contained bright, complex arrays of Glu-MTs (l) compared to antisense-treated myocytes not expressing GFP-h-MURF-2 (Fig. 3A,h). Bar, 10 µm.