Eukaryotic ribosome assembly requires over 200 assembly factors that facilitate rRNA folding, ribosomal protein binding, and pre-rRNA processing. One such factor is Rlp7, an essential RNA binding protein required for consecutive pre-rRNA processing steps for assembly of yeast 60S ribosomal subunits: exonucleolytic processing of 27SA3 pre-rRNA to generate the 5' end of 5.8S rRNA and endonucleoly...

Repeated sequences, like the 5.8S rRNA and its flanking regions in C. albicans, can be of particular interest as PCR targets; this is especially true if variations in sequence or length of these regions occur between members of a same genus or species (1). We therefore cloned ribosomal repetitive units of two C. albicans strains and determined the sequence of their respective Internal Transcrib...

PCR amplification and sequencing of phylogenetic markers, primarily Small Sub-Unit ribosomal RNA (SSU rRNA) genes, has been the paradigm for defining the taxonomic composition of microbiomes. However, 'universal' SSU rRNA gene PCR primer sets are likely to miss much of the diversity therein. We sequenced a library comprising purified and reverse-transcribed SSU rRNA (RT-SSU rRNA) molecules from...

We have isolated and partially characterized an endonuclease involved in processing the 5' end of 16S rRNA of Escherichia coli. A mutant strain that is deficient in this enzyme accumulates a new precursor of 16S rRNA, named 16.3S rRNA. This rRNA has the 3' end of mature 16S rRNA but is about 60 nucleotides longer at the 5' end. In vitro, the enzyme preparation cleaves an RNA fragment of about 6...

The gene encoding the 5S rRNA for Leptospira interrogans serovar canicola strain Moulton was isolated and sequenced. The 5S rRNA gene occurs as a single copy within the genome and encodes a 117-nucleotide-long RNA molecule. The 5S rRNA gene is flanked at both the 5' and 3' ends by regions of A + T-rich sequences, and the 5'-flanking region contains a promoter sequence. L. interrogans has a uniq...

The sequence of 300 nucleotides surrounding the transcription termination site for ribosomal RNA in Drosophila melanogaster has been determined. The precise position of the RNA 3'-end was located by sizing rDNA fragments protected from S1 nuclease by hybridization with cytoplasmic 28S rRNA or with nuclear 38S pre-rRNA. Next, the sequence of the first 10 nucleotides at the 3'-end of 28S and 38S ...

SIRT7 is an NAD(+)-dependent protein deacetylase with important roles in ribosome biogenesis and cell proliferation. Previous studies have established that SIRT7 is associated with RNA polymerase I, interacts with pre-ribosomal RNA (rRNA) and promotes rRNA synthesis. Here we show that SIRT7 is also associated with small nucleolar RNP (snoRNPs) that are involved in pre-rRNA processing and rRNA m...

Recently, Cangelosi and Brabant used oligonucleotide probes targeting the precursor 16S rRNA of Escherichia coli to demonstrate that the levels of precursor rRNA were more sensitive to changes in growth phase than the levels of total rRNA (G. A. Cangelosi and W. H. Brabant, J. Bacteriol. 179:4457-4463, 1997). In order to measure changes in the levels of precursor rRNA in activated sludge system...

To investigate the function of the nucleolar protein Nop2p in Saccharomyces cerevisiae, we constructed a strain in which NOP2 is under the control of a repressible promoter. Repression of NOP2 expression lengthens the doubling time of this strain about fivefold and reduces steady-state levels of 60S ribosomal subunits, 80S ribosomes, and polysomes. Levels of 40S subunits increase as the free po...