RNA processing in the minimal organism Nanoarchaeum equitans.
BACKGROUND
The minimal genome of the tiny, hyperthermophilic archaeon Nanoarchaeum equitans contains several fragmented genes and revealed unusual RNA processing pathways. These include the maturation of tRNA molecules via the trans-splicing of tRNA halves and genomic rearrangements to compensate for the absence of RNase P.


RESULTS
Here, the RNA processing events in the N. equitans cell are analyzed using RNA-Seq deep sequencing methodology. All tRNA half precursor and tRNA termini were determined and support the tRNA trans-splicing model. The processing of CRISPR RNAs from two CRISPR clusters was verified. Twenty-seven C/D box small RNAs (sRNAs) and a H/ACA box sRNA were identified. The C/D box sRNAs were found to flank split genes, to form dicistronic tRNA-sRNA precursors and to be encoded within the tRNAMet intron.


CONCLUSIONS
The presented data provide an overview of the production and usage of small RNAs in a cell that has to survive with a highly reduced genome. N. equitans lost many essential metabolic pathways but maintains highly active CRISPR/Cas and rRNA modification systems that appear to play an important role in genome fragmentation.
Lennart
L
Randau
D019843:Archaeal Proteins / Q000378:metabolism; D064113:CRISPR-Cas Systems; D019143:Evolution, Molecular; D020745:Genome, Archaeal; D059014:High-Throughput Nucleotide Sequencing; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046588:Nanoarchaeota / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D012323:RNA Processing, Post-Transcriptional; D019642:RNA, Archaeal / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D012343:RNA, Transfer / Q000737:chemistry / Q000378:metabolism; D017423:Sequence Analysis, RNA; D020040:Trans-Splicing
D019843:Archaeal Proteins; D019642:RNA, Archaeal; D012343:RNA, Transfer