Analysis of synemin isoforms after neural differentiation of mouse ES cells. A, RT-PCR analysis of mRNA encoding synemins H, M and L isoforms, nestin, and GFAP in retinoic acid (RA) treated (+) and control (-) EBs. Synemin M mRNA was found in both control and differentiated ES cells, while synemin H, synemin L, nestin and GFAP mRNA were found only in differentiated ES cells (+) and absent in control ES cells (-). B, Western blotting analysis of synemins (H, M and L), nestin, GFAP and β-III tubulin proteins extracted from RA treated (+) and control (-) EBs. Synemins H and L, nestin, GFAP, and β-III tubulin proteins were detected in retinoic acid treated (+) EBs and absent in control (-) EBs. An increase of synemin M protein was observed in EBs after retinoic acid treated (+). α-tubulin was used for the loading control. Syn: synemin; Nes: nestin; βIII Tub: β-III tubulin; α-Tub: α-tubulin.