21 research outputs found
Higher Expression Level and Lower Toxicity of Genetically Spliced Rotavirus NSP4 in Comparison to the Full-Length Protein in E. coli
Effects of striatal transplantation of cells transfected with GDNF gene without pre- and pro-regions in mouse model of Parkinson’s disease
Purification of the cleavage and polyadenylation factor involved in the 3'-processing of messenger RNA precursors
Polyadenylation of messenger RNA precursors requires the nucleotide sequence AAUAAA and two factors: poly(A) polymerase and a specificity factor termed cleavage and polyadenylation factor (CPF). We have purified CPF from calf thymus and from HeLa cells to near homogeneity. Four polypeptides with molecular masses of 160, 100, 73, and 30 kDa cofractionate with CPF activity. Glycerol gradient centrifugation and gel filtration indicate that these four proteins form one large complex with a sedimentation constant of 12 S, a Stokes radius near 100 A, and a native molecular mass near 500 kDa. Purified CPF binds specifically to an RNA that contains the AAUAAA sequence. Mutation of the AAUAAA sequence inhibits CPF binding as well as polyadenylation. Purified CPF contains only trace amounts of RNA and does not react with antibodies against common epitopes of small nuclear ribonucleoprotein particles. Thus, contrary to previous indications, CPF does not appear to be a small nuclear ribonucleoprotein particle