Altered fractionation profiles of higher plant poly(A)-containing RNA by selective formation of a complex with a hydrophobic impurity

Synthetic polyadenylate (poly(A)) which originally sedimented at 6–7 S in a sucrose density gradient did so at 15–19 S in the presence of phenol-extracted nucleic acids from higher plant tissues. After centrifugation, the input poly(A) was found to be insensitive to RNase T2 (EC 3.129.1), suggesting a newly-formed complex with a hydrophobic substance contaminating the nucleic acid preparation. The artifically-formed poly(A)-impurity complex migrated more slowly than unbound poly(A) during gel electrophoresis. The complex was retained rather effectively by an oligodeoxythymidylate (oligo-(dT))-cellulose column and a polyuridylate (poly(U))-glassfiber filter. However, a nitrocellulose membrane filter retained the poly(A)-complex to various extents depending on plant materials, suggesting different varieties of the poly(A)-binding impurity in the higher plant kingdom. Fractionation of mRNA by these ordinarily used procedures is suggested to be variously altered by complex formation with this hydrophobic impurity.