Nucleic Acids Research, 1981, Vol. 9, No. 4 789-799
© 1981
MOLECULAR BIOLOGY |
The structure of the yeast ribosomal RNA genes. 3. Precise mapping of the 18 S and 25 S rRNA genes and structure of the adjacent regions
Institute of Molecular Biology, Academy of Sciences of the USSR Vavilov str. 32, Moscow B-312, USSR *Institute of Molecular Biology, Bulgarian Academy of Sciences 1113 Sofia, Bulgaria
Received December 29, 1980. The 5'-termini of Saccharomyces cerevisiae 18 S and 25 S rRNA are precisely mapped within the sequence of the rDNA repeating unit. The 3'-termini of 25 S rRNA and 37 S pre-rRNA are located within a 548 bp segment of the rDNA repeating unit by the use of a DNA polymerase I extension technique. The analysis of the rDNA sequences at the structural gene boundaries reveals the presence of oligonucleotide repeats which may be involved in transcription or processing control mechanisms. The sequence of rDNA in the transcription termination region is determined and possible mechanisms shaping the 3'-end of 25 S rRNA are discussed.