Fig. 1. Transcription analysis of Mash1 in ES and neural cells. (A) RT-PCR of Mash1 and control genes from OS25 ES and neural cell RNA. After 30 cycles of PCR Mash1 is detected in the neural but not the ES sample. Markers for ES to neural differentiation, Oct4, Sox2 and Sox1, show expected expression patterns. ß-actin was used as a template input control. -RT, reverse-transcriptase-free negative control. (B) Semi-quantitative RT-PCR shows that transcription of Mash1 occurs at a negligible level in ES cells but is dramatically upregulated (at least 125-fold) in neural cells. Dilutions were: 1, 1:5, 1:25, 1:125, left to right. S26, small ribosomal protein 26 template-input control. E15 head, positive control for Mash1 expression. dH₂O, negative control.