Polyadenylic Acid‐containing Rna From Rat Brain

A portion of rat brain RNA contains poly(A) sequences and binds to oligo(dT)‐cellulose. Young rats have a greater amount of brain RNA which contains poly(A) than do adult animals. The length of the poly(A) sequence from the brain RNA of young animals was shown to be somewhat longer than that from the RNA of adults. The RNA which bound to the oligo(dT)‐cellulose was found to be large and heterogeneous, and to be almost free of ribosomal or of small mol. wt. RNAs. When the polysomal RNA which bound to the oligo(dT)‐cellulose columns and that which did not were used to prime a cell‐free protein synthesizing system there was a noticeable difference in their‘messenger’activity; the RNA which bound to the oligo(dT)‐cellulose was much more active than the unbound material. However, in the case of the nuclear RNA there was not as great a difference between the material which was bound and that which was not bound.