Open Access5′‐Ends of Ribosomal and Ribosomal Precursor RNAs from Xenopus laevis
Author(s) -
Slack Jonathan M. W.,
Loening Ulrich E.
Publication year - 1974
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1974.tb03384.x
Subject(s) - ribosomal rna , xenopus , rna , microbiology and biotechnology , biochemistry , uridine triphosphate , biology , uridine , polynucleotide , ribosome , rna polymerase i , chemistry , nucleotide , rna polymerase , gene
The 5′‐ends of 18‐S, 28‐S and 40‐S RNA from Xenopus laevis have been studied by two techniques. The first involves fractionation of alkaline hydrolysates on columns of DEAE‐Sephadex at pH 7.8 and 2.7, followed by thin‐layer chromatography on polyethyleneimine cellulose. The second involves labelling in vitro of the RNA species at the 5′‐end using polynucleotide kinase. The 40‐S molecule is shown not to bear a terminal 5′‐triphosphate. It has the 5′‐terminus guanosine 5′‐phosphate. Both the 18 and 28‐S RNAs have the 5′‐terminus uridine 5′‐phosphate. The 28‐S RNA has the 5′‐terminal sequence pU‐N‐N‐N‐Gp. These results are discussed in relation to the transcription of the ribosomal genes, the possible heterogeneity of the ribosomal precursor and the position of the 28‐S sequence within the precursor molecule.