Figure 5.

Model for telomere capping complexes in the flowering plant Arabidopsis thaliana and the moss Physcomitrella patens. (A) CST functions as the major telomere capping complex in Arabidopsis. Multiple TRF-like proteins have been described, but other shelterin-like components cannot be identified in plant genomes. POT1a is a telomerase accessory factor and is not required for chromosome end protection. (B) P. patens encodes two TRF-like proteins and a single POT1 protein. The moss POT1 binds single-stranded G-rich telomeric DNA and functions in a manner analogous to vertebrate and yeast POT1. CST components are encoded in the P. patens genome, but their function is unknown.