摘要：

Wheat germ ribosomes can bind to reovirus messenger RNAs, protecting a limited region of each message against digestion by T 1 RNAase. From the medium size class of reovirus mRNA, which includes three messenger species, three protected fragments were recovered from 40 S initiation complexes; and each of the fragments included the 5′-terminal methylated "cap", m 7G(5′)-ppp(5′)G m-C. Two of the 40 S ribosome-protected fragments, consisting of 52 and 44 nucleotides, were sequenced. Each of these fragments contained an AUG codon and was capable of re-binding to ribosomes. The two ribosome-protected fragments showed limited sequence homology. Two of the fragments recovered from 80 S initiation complexes with the medium size class of reovirus RNA were also sequenced. The sequences of each message protected by 80 S ribosomes were a subset of those protected by 40 S ribosomes. With the two messages studied in greatest detail, 80 S ribosomes failed to protect the 5′-terminal region of either message, and in one case, the 3′-terminal portion of the fragment protected by 40 S ribosomes also was not protected within 80 S initiation complexes.

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