Open AccessThe Ribosomal‐RNA‐Processing Pathway in Schizosaccharomyces Pombe
Author(s) -
Good Liam,
Intine Robert V. A.,
Nazar Ross N.
Publication year - 1997
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1997.00314.x
Subject(s) - ribosome biogenesis , schizosaccharomyces pombe , 5.8s ribosomal rna , biology , ribosomal rna , rna , ribosome , internal transcribed spacer , genetics , schizosaccharomyces , microbiology and biotechnology , computational biology , yeast , gene , saccharomyces cerevisiae
In all cells, a long precursor RNA is processed into mature rRNAs for ribosome biogenesis. In eukaryotes, the complexity and speed of the overall process often has made it difficult to establish finer details of the maturation pathway. Since phylogenetic comparisons can provide evidence for critical events, the major rRNA processing pathway for the yeast Schizosaccharomyces pombe was determined using primer extension, nuclease protection and Northern‐hybridisational analyses. Transcript mapping of the 5′ external transcribed spacer revealed six cleavage sites which occur upstream of the mature 18S termini. Two of these sites as well as a site adjacent to the 18S termini are complementary to conserved Box sequences in the S. pombe U3 small nucleolar RNA. Transcript mapping of the internal transcribed spacers (1 and 2) suggest similar maturation schemes for the two spacers, in which an initial endonuclease cleavage is followed by processing to the mature termini. The mature 5′ termini of 25S rRNA appear to be heterogeneous in S. pombe , as has been demonstrated for 5.8S rRNA, suggesting an essential limiting structure in the ribosome‐integrated mature RNA. Together with our previous analysis of the 3′ external spacer region, the results reveal the major processing pathway for S. pombe and further support a maturation process which acts as a quality assurance mechanism.