Omnipotent RNA.

FEBS Lett 2002 Oct 23;530(1-3):4-8 Related Articles, Links

Spirin AS.

Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia. spirin@vega.protres.ru

The capability of polyribonucleotide chains to form unique, compactly folded structures is considered the basis for diverse non-genetic functions of RNA, including the function of recognition of various ligands and the catalytic function. Together with well-known genetic functions of RNA - coding and complementary replication - this has led to the concept of the functional omnipotence of RNA and the hypothesis that an ancient RNA world supposedly preceded the contemporary DNA-RNA-protein life. It is proposed that the Woese universal precursor in the ancient RNA world could be a cell-free community of mixed RNA colonies growing and multiplying on solid surfaces.

PMID: 12387857

4. Small nucleolar RNAs: versatile trans-acting molecules of ancient evolutionary origin.
Terns MP, Terns RM.Gene Expr 2002;10(1-2):17-39
Department of Biochemistry and Molecular Biology, University of Georgia, Athens 30602, USA. mterns@bmb.uga.edu

The small nucleolar RNAs (snoRNAs) are an abundant class of trans-acting RNAs that function in ribosome biogenesis in the eukaryotic nucleolus. Elegant work has revealed that most known snoRNAs guide modification of pre-ribosomal RNA (pre-rRNA) by base pairing near target sites. Other snoRNAs are involved in cleavage of pre-rRNA by mechanisms that have not yet been detailed. Moreover, our appreciation of the cellular roles of the snoRNAs is expanding with new evidence that snoRNAs also target modification of small nuclear RNAs and messenger RNAs. Many snoRNAs are produced by unorthodox modes of biogenesis including salvage from introns of pre-mRNAs. The recent discovery that homologs of snoRNAs as well as associated proteins exist in the domain Archaea indicates that the RNA-guided RNA modification system is of ancient evolutionary origin. In addition, it has become clear that the RNA component of vertebrate telomerase (an enzyme implicated in cancer and cellular senescence) is related to snoRNAs. During its evolution, vertebrate telomerase RNA appears to have co-opted a snoRNA domain that is essential for the function of telomerase RNA in vivo. The unique properties of snoRNAs are now being harnessed for basic research and therapeutic applications.
PMID: 11868985 [PubMed - indexed for MEDLINE]

Существуют особые коротенькие РНК, которые участвуют в мдоификации рРНК, т.е., короче, в формировании рибосом. Причем они есть у Эукариот и Археа (указывает на некую связь между ними).

5. Archaeal translation initiation revisited: the initiation factor 2 and eukaryotic initiation factor 2B alpha-beta-delta subunit families.
Kyrpides NC, Woese CR.Proc Natl Acad Sci U S A 1998 Mar 31;95(7):3726-30
Department of Microbiology, University of Illinois at Urbana-Champaign, B103 Chemical and Life Sciences, MC 110, 407 S. Goodwin, Urbana, IL 61801, USA. nikos@darwin.life.uiuc.edu

As the amount of available sequence data increases, it becomes apparent that our understanding of translation initiation is far from comprehensive and that prior conclusions concerning the origin of the process are wrong. Contrary to earlier conclusions, key elements of translation initiation originated at the Universal Ancestor stage, for homologous counterparts exist in all three primary taxa. Herein, we explore the evolutionary relationships among the components of bacterial initiation factor 2 (IF-2) and eukaryotic IF-2 (eIF-2)/eIF-2B, i.e., the initiation factors involved in introducing the initiator tRNA into the translation mechanism and performing the first step in the peptide chain elongation cycle. All Archaea appear to posses a fully functional eIF-2 molecule, but they lack the associated GTP recycling function, eIF-2B (a five-subunit molecule). Yet, the Archaea do posses members of the gene family defined by the (related) eIF-2B subunits alpha, beta, and delta, although these are not specifically related to any of the three eukaryotic subunits. Additional members of this family also occur in some (but by no means all) Bacteria and even in some eukaryotes. The functional significance of the other members of this family is unclear and requires experimental resolution. Similarly, the occurrence of bacterial IF-2-like molecules in all Archaea and in some eukaryotes further complicates the picture of translation initiation. Overall, these data lend further support to the suggestion that the rudiments of translation initiation were present at the Universal Ancestor stage.
PMID: 9520434 [PubMed - indexed for MEDLINE]

Важно: факты в пользу того, что трансляция (т.е. синтез белка) присутствовала уже у "последнего общего предка", т.е. жизнь разошлась на линии Археа, Бактериа и Эукариа уже на такой стадии, когда были белки, а не только РНК

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