Mapping RNA Regions in Eukaryotic Ribosomes That Are Accessible to Methidiumpropyl-EDTA•Fe(II) and EDTA•Fe(II)
Methidiumpropyl-EDTA•Fe(II) [MPE.Fe(II)] and EDTA•Fe(II) were used to investigate the structure of Drosophila melanogaster ribosomes. Cleavage reactions were performed on intact ribosomes in cell lysates in vitro and analyzed by primer extension with reverse transcriptase using oligodeoxynucleotide primers. Regions of 18S and 28S ribosomal RNAs (rRNAs) which are accessible to MPE•Fe(II) and EDTA•Fe(II) are located almost exclusively within expansion segments. The accessibility of these regions to cleavage indicates that they are likely exposed on the surface of eukaryotic ribosomes. These results provide information about the overall tertiary structure of rRNA in ribosomes.
© 1994 American Chemical Society. Received April 4, 1994; Revised Manuscript Received May 31, 1994. Abstract published in Advance ACS Abstracts, August 1, 1994. This research was supported by National Institutes of Health grants [GM-27681 (P.B.D.) and GM-45299, 40857 (M.P.)] and by an NIH postdoctoral fellowship (GM-11646-02) to AS. We thank Drs. Lorna Neilson, Shawn Vallett, and Heather W. Weber for helpful discussions. We are grateful to Dr. Robin R. Gutell for providing secondary structural models.