Distinctive features in the SelB family of elongation factors for
selenoprotein synthesis. A glimpse of an evolutionary complexified translation
apparatus
Affiliations: Unité Propre de Recherche 9002 du CNRS, Structure
des Macromolécules Biologiques et Mécanismes de Reconnaissance, Institut de
Biologie Moléculaire et Cellulaire, 15, Rue René Descartes, 67084
Strasbourg Cedex, France
Abstract: The last ten years have seen a dramatic increase in our
understanding of the molecular mechanism allowing specific incorporation of
selenocysteine into selenoproteins. Whether in prokaryotes or eukaryotes, this
incorporation requires several gene products, among which the specialized
elongation factor SelB and the tRNA^{\rm Sec} play a pivotal
role. While the molecular actors have been discovered and their role elucidated
in the eubacterial machinery, recent data from our and other laboratories
pointed to a higher degree of complexity in archaea and eukaryotes. These
findings also revealed that more needs to be discovered in this area. This review will focus on phylogenetic aspects of the SelB proteins.
In particular, we will discuss the concerted evolution that occurred within the
SelB/tRNA^{\rm Sec} couples, and also the distinctive roles
carried out by the SelB C-terminal domains in eubacteria on the one side, and
archaea and eukaryotes, on the other.
