The algal selenoproteomes

Abstract

Background:Selenium is an essential trace element, and selenocysteine (Sec, U) is its predominant form in vivo. Proteins that contain Sec are selenoproteins, whose special structural features include not only the TGA codon encoding Sec, but also the SECIS element in mRNA and the conservation of the Sec flanking region. These unique features have led to developing a series of bioinformatics methods to predict and research selenoprotein genes. There are some studies and reports on the evolution and distribution of selenoprotein genes in prokaryotes and multicellular eukaryotes, but the systematic analysis of single-cell eukaryotes, especially algae, is very limited.Results:In this study, we predicted selenoprotein genes in 137 species of algae by using a program we previously developed. More than 1000 selenoprotein genes were obtained. A database website was built to hold these algae selenoprotein genes (www.selenoprotein.com). These genes belong to 42 selenoprotein families, including three novel selenoprotein gene families.Conclusions:This study reveals the primordial state of the eukaryotic selenoproteome. It is an important clue to explore the significance of selenium for primordial eukaryotes and to build the whole evolutionary spectrum of selenoproteins for all life.

Scientific opinion on the tolerable upper intake level for selenium

“…Plants generally do not have UGA‐encoded selenoproteins (White, 2018). With exception of some algae (Jiang et al., 2020), selenoproteins can only be synthesised in animals and some microorganisms (Beilstein and Whanger, 1986; Combs, 2015).…”