Fibrillarin

Nop1p/Fibrillarin was originally identified as a nucleolar protein of bakers yeast, Saccharomyces cerevisiae (accession P15646). The Nop1p protein is 327 amino acids in size (34.5kDa), is essential for yeast viability, and is localized in the nucleoli. Nop1p is the yeast homologue of a protein apparently found in all eukaryotes and archaea generally called fibrillarin. Fibrillarin/Nop1p is extraordinarily conserved, so that the yeast and human proteins are 67% identical, and the human protein can functionally replace the yeast protein. This antibody is becoming widely used as a convenient marker for nucleoli in a wide variety of species (e.g. 4-6). The HGNC name for this protein is FBL. To raise the fibrillarin antibody, mice were injected with full length recombinant human fibrillarin.