Translation initiation in Archaea: conserved and domain-specific features.
Initiation is a critical step in translation, during which the ribosome lands on the start codon and sets the correct reading frame for mRNA decoding. The rate and efficiency of translation are largely determined by initiation, which is therefore the preferred target of translation regulation mechanisms. Initiation has incurred an extensive evolutionary divergence among the primary domains of cell descent. The Archaea, albeit prokaryotes, have an initiation mechanism and apparatus more complex than those of the Bacteria; the molecular details of archaeal initiation are just beginning to be unravelled. The most notable aspects of archaeal initiation are the presence of two, perhaps three, distinct mechanisms for mRNA-ribosome interaction and the presence of a relatively large set of IFs (initiation factors), several of which are shared exclusively with the Eukarya. Among these, the protein termed a/eIF2 (archaeal/eukaryotic IF2) and aIF6 (archaeal IF6) are of special interest, since they appear to play key regulatory roles in the Eukarya. Studies of the function of these factors in Archaea have uncovered new features that will help to elucidate their conserved and domain-specific functions.
Department of Cell Biotechnologies and Haematology, University of Rome Sapienza, Policlinico Umberto 1, Viale Regina Elena 324, 00161 Rome, Italy.
Dario
D
Benelli
Paola
P
Londei
D001105:Archaea / Q000235:genetics / Q000378:metabolism*; D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D015852:Eukaryotic Initiation Factor-2 / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D010448:Peptide Initiation Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014176:Protein Biosynthesis; D011487:Protein Conformation; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D012333:RNA, Messenger / Q000737:chemistry / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism
D019843:Archaeal Proteins; D001426:Bacterial Proteins; D015852:Eukaryotic Initiation Factor-2; D010448:Peptide Initiation Factors; D021122:Protein Subunits; D012333:RNA, Messenger