Association of D-RNA with Polyribosomes in the Soybean Root.

Ribosomes from soybean root tips were shown to consist of about 75% polyribosomes based on size distribution on sucrose gradients. Electronmicrographs showed the presence of ribosome clusters in normal preparations and only monomers and dimers in ribonuclease-treated preparations. The polyribosome preparations, but not single ribosomes, showed good in vitro amino acid incorporating activity.D-RNA was associated with the ribosome preparations, and preferentially in the polyribosome structure. It is suggested that at least a part of the soybean D-RNA represents a class of messenger RNA.