Selenoproteins are proteins that contain selenocysteine (Sec, U), a non-canonical amino acid which has structural similarity to cysteine (Cys). Sec is encoded by the UGA codon, which normally signs for translation termination. Given this condition, selenoproteins must contain a SECIS sequence (SelenoCysteine Insertion Sequence), a conserved stem-loop structure, in their 3’UTR region for the recognition of the UGA codon as a Sec-coding codon rather than as a STOP signal. The ensemble of all selenoproteins constitutes the selenoproteome, which is highly conserved among living beings.
The aim of this project was to characterize the selenoproteome of Paroedura picta, a terrestrial gecko that lives in the forests of Madagascar, using an homology-based approach. Paroedura picta’s genome was compared to the Homo sapiens selenoproteome and selenoprotein-related genes, and was further analyzed to perform their annotation using bioinformatic tools such as the tblastn, Exonerate, T-Coffee and Seblastian softwares.
Results were obtained showing a high conservation between Homo sapiens and Paroedura picta in most of their selenoproteins as well as the selenoprotein-synthesis machinery, despite displaying some non-conserved genes or Cys-containing protein homologues.
This characterization constitutes the first approach for the annotation of the selenoproteome in Paroedura picta, which contributes to the global objective to properly annotate the genome of all vertebrates on Earth in the forthcoming years.
Human Biology (Universitat Pompeu Fabra) - 2021