The presence of polyriboadenylic acid sequences in calf lens messenger RNA

Abstract

The presence of poly(rA) sequences in lens RNA has been demonstrated by the isolation of RNase A and T 1-resistant fragments of approximately 50 nucleotide residues. These poly(rA)-rich sequences, obtained from lenses incubated for six hours in organ culture with [ 3H]adenosine, are located at the 3′ termini of mRNA as determined by 3′ exoribonuclease digestion. Limited digestion of the [ 3H]adenosine-labeled mRNA with the enzyme led to the abolition of binding to poly(rU)-filters and a concomitant loss of template activity with avian myeloblastosis virus RNA-dependent DNA polymerase. Furthermore, after incubation of lenses in organ culture with 3′-deoxyadenosine, the isolated polysomal RNA was unable to function as a template in an avian myeloblastosis virus RNA-dependent DNA polymerase-catalyzed reaction system.