Comparative biology of telomeres: where plants stand

Abstract

Telomeres are essential structures at the ends of eukaryotic chromosomes. Work on their structure and function began almost 70 years ago in plants and flies, continued through the Nobel Prize winning work on yeast and ciliates, and goes on today in many model and non-model organisms. The basic molecular mechanisms of telomeres are highly conserved throughout evolution, and our current understanding of how telomeres function is a conglomeration of insights gained from many different species. This review will compare the current knowledge of telomeres in plants with other organisms, with special focus on the functional length of telomeric DNA, the search for TRF homologs, the family of POT1 proteins, and the recent discovery of members of the CST complex.

Fig. 1

Structural comparison of the DNA binding domains of NgTRF1 in green and human TRF1 in yellow. Circled in red is the loop between helix 3 and 4 which directly contacts the DNA minor groove and provides binding specificity to the plant telomeric sequence TTTAGGG. Reprinted from Ko et al. (2008) Nucl. Acids Res. 36, 2739–2755 with permission from Oxford University Press.