FIG. 1.

ETn and MusD transcript abundance in undifferentiated and differentiated cell lines. (A) Northern blot. Ten micrograms of RNA isolated from EC P19, ES R1, and fibroblast NIH 3T3 cells was hybridized with ETnI, ETnII-β, MusD, or β-actin probes. ETnII-β and MusD probes produced single bands, and the ETnI probe produced a single major band of 5.6 kb and a minor band of 7.2 kb. The blot was initially hybridized with an ETnII-β oligonucleotide probe, then stripped and rehybridized in turn with the other indicated probes. (B) Structures of ETn elements and locations of probes used in Northern blotting.