Protection of telomeres 1 (POT1) of Pinus tabuliformis bound the telomere ssDNA

Protection of telomeres 1 (POT1) is a telomeric protein that binds to the telomere single-stranded (ss) region. It plays an essential role in maintaining genomic stability in both plants and animals. In this study, we investigated the properties of POT1 in Pinus tabuliformis Carr. (PtPOT1) through electrophoretic mobility shift assay. PtPOT1 harbored affinity for telomeric ssDNA and could bind plant- and mammalian-type ssDNA sequences. Notably, there were two oligonucleotide/oligosaccharide binding (OB) folds, and OB1 or OB2 alone, or both together, could bind ssDNA, which is significantly different from human POT1. Based on our data, we hypothesized that the two OB folds of PtPOT1 bound the same ssDNA. This model not only provides new insight into the ssDNA binding of PtPOT1 but also sheds light on the functional divergence of POT1 proteins in gymnosperms and humans.