Putative telomere proteins encoded in the Stylophora
pistillata genome
To characterize the structure of coral telomeres, we searched in theS. pistillata host genome (Voolstra et al. 2017) for genes
encoding putative shelterin subunits as well as the telomerase catalytic
subunit TERT. We identified orthologs of four human shelterin subunits
(Rap1, Trf1/2, Pot1, Tpp1 ) and of Tert (Figure
1A-B-C-D-E). The coral genome contains two human Pot1 paralogs,
similarly to mouse and Caenorhabditis elegans elegans (Raiceset al. 2008), and only one Trf , in agreement with the
duplication of the Trf ancestor in Trf1 and Trf2that occurred at the base of the chordate lineage (Poulet et al.2012) (Figure 1B). The coral Pot1 protein shares a similar structure
with the human Pot1, containing two
Oligonucleotide/Oligosaccharide-Binding (OB) fold domains located in the
N-terminal region and a characteristic split OB fold in the C-terminus
(Figure1-G, Supplementary Figure 1). The second ortholog of Pot, named
Pot2, contains two OB folds skewed to the C-terminal part of the
protein. Therefore, the protein composition of coral telomeres is likely
to share many similarities to those of other animals (Figure 1F).