5S ribosomal RNA gene repeats are arranged in heterochromatic arrays (5S rDNA) situated near the centromeres of Arabidopsis chromosomes. The chromatin remodeling factor DDM1 is known to maintain 5S rDNA methylation patterns while silencing transcription through 5S rDNA intergenic spacers (IGS). We mapped small-interfering RNAs (siRNA) to a composite 5S rDNA repeat, revealing a high density of s...

Ribosomal 5S RNA (5S rRNA) is an integral component of the large ribosomal subunit in all known organisms with the exception only of mitochondrial ribosomes of fungi and animals. It is thought to enhance protein synthesis by stabilization of a ribosome structure. This paper presents the updated database of 5S rRNA and their genes (5S rDNA). Its short characteristics are presented in the Introdu...

Using the nematode Caenorhabditis elegans as a model organism, we have prepared cell-free extracts which accurately transcribe cloned homologous 5S RNA genes in vitro. These extracts also transcribe cloned tRNA genes, and actively process the resulting products. Unlike tRNA genes, transcription of 5S DNA shows some species specificity: C. elegans extracts do not transcribe Xenopus 5S RNA genes,...

5S ribosomal RNA specifically inhibits transcription of cloned repeating units of 5S DNA in a nuclear extract of Xenopus oocytes. The inhibition can be explained by the interaction of 5S RNA with a transcription factor that binds specifically to a control region located within the 5S RNA gene. This transcription factor is identical to an abundant cytoplasmic protein that is known to be complexe...

The repetitive zinc finger domain of transcription factor IIIA binds 5S DNA and 5S RNA with similar affinity. Site directed mutagenesis of the Xenopus borealis somatic 5S RNA gene has been used to produce a series of derivatives of 5S RNA containing local sequence substitutions or sequence deletions. Gel mobility shift analyses of the binding of TFIIIA to these altered 5S RNAs revealed that all...

During 60S biogenesis, mature 5S RNP consisting of 5S RNA, RpL5 and RpL11, assembles into a pre-60S particle, where docking relies on RpL11 interacting with helix 84 (H84) of the 25S RNA. How 5S RNP is assembled for recruitment into the pre-60S is not known. Here we report the crystal structure of a ternary symportin Syo1-RpL5-N-RpL11 complex and provide biochemical and structural insights into...

The Arabidopsis thaliana genome comprises around 1,000 copies of 5S rRNA genes encoding both major and minor 5S rRNAs. In mature wild-type leaves, the minor 5S rRNA genes are silent. Using different mutants of DNA methyltransferases (met1, cmt3 and met1 cmt3), components of the RNAi pathway (ago4) or post-translational histone modifier (hda6/sil1), we show that the corresponding proteins are ne...

The maturation of 5S RNA in Escherichia coli is poorly understood. Although it is known that large precursors of 5S RNA accumulate in mutant cells lacking the endoribonuclease-RNase E, almost nothing is known about how the mature 5' and 3' termini of these molecules are generated. We have examined 5S RNA maturation in wild-type and single- or multiple-exoribonuclease-deficient cells by Northern...