- At least three linear regions but not the zinc-finger domain of U1C protein are exposed at the surface of the protein in solution and on the human spliceosomal U1 snRNP particle. Dumortier, H., Klein Gunnewiek, J., Roussel, J.P., van Aarssen, Y., Briand, J.P., van Venrooij, W.J., Muller, S. Nucleic Acids Res. (1998)