Size heterogeneity of ribosomal RNA in eukaryote evolution--2. rRNA molecular weights in species containing discontinuous large ribosomal subunit RNA.
1. The molecular weights and the integrity of the principal rRNA species derived from the large and small ribosomal subunit (respectively, L-rRNA and S-rRNA) of several species of Protostomia and Protozoa have been investigated. 2. Using gel electrophoresis in formamide, the molecular weights of protostomian L-rRNA species have been found to range from 1.30 X 10(6) (Annelida) to 1.61 X 10(6) (Diptera); those of the S-rRNA's cover the range 0.65 X 10(6) (Annelida)-0.81 X 10(6) (Diptera). 3. Both rRNA components have incurred extensive changes among the Protozoa; the L-rRNA ranges in weight from 1.35 X 10(6) (T. pyriformis) to 1.57 X 10(6) (A. castellanii) and the S-rRNA from 0.70 X 10(6) of T. pyriformis to 0.85 X 10(6) of A. castellanii and E. gracilis. 4. The L-rRNA components of all the species investigated are discontinuous molecules endowed with a latent median break; depending on whether the nick is located at the centre of the L-rRNA chain, or lies off-centre, the molecular weight of the S-rRNA equals that of either both, or only one, of the two fragments composing the L-rRNA.
D000818:Animals; D002477:Cells / Q000032:analysis*; D004591:Electrophoresis, Polyacrylamide Gel; D056890:Eukaryota; D005057:Eukaryotic Cells / Q000032:analysis*; D046911:Macromolecular Substances; D008970:Molecular Weight; D010271:Parasites; D012335:RNA, Ribosomal / Q000032:analysis*; D013045:Species Specificity
D046911:Macromolecular Substances; D012335:RNA, Ribosomal