Abstract

The most relevant biological form of selenium is the selenocysteine aminoacid (1), which is included in the so called selenoproteins. These are found to play main roles in several metabolism processes in all three kingdoms of life but plants and yeast (2–5). Furthermore the selenoproteome constitute a putative tool for evolutionary studies, due to its differential distribution among lineages.

The aim of our project is to asses the characteristics of the selenoproteome of Prophitecus coquereli, an endemic lemur from Madagascar Island. We also aim to annotate each selenoprotein found on Prophitecus coquereli’s recently-sequenced genome.

In order to achieve our objectives we performed a local alignment (BLAST) of the Homo sapiens selenoproteome against Prophitecus coquereli’s genome. We then analyzed the output and automatized the TCOFFEE alignment of the best hit for each selenoprotein.

Our results show a high conservation of the selenoproteome of primates in Prophitecus coquereli, 25 selenoproteins have been found on its genome, observing putative duplications or retrotransposition of SelW and SelI, as well as the selenocysteine-synthesis-machinery protein SPS2. Also loss of selenocysteine has occurred in SelS and a possible isoform of SelW.

Selenocysteine inclusion depends on the presence of a secondary RNA structure called SECIS element, this is a necessary condition for a protein containing selenocysteine codon to become a selenoprotein (2–4). Some proteins of the selenoproteome of H.sapiens have been shown to lack this element (GPx6).

We therefore consider this study as a valuable source of information for future research in the field of selenoproteins and their conservation. Especially regarding the evolutionary pattern of Prophitecus coquereli.

Key words: Selenoprotein, Selenoproteome, Prophitecus coquereli, TCOFFEE, BLAST.