Xiangyu Song
Hometown:
Yingkou, Liaoning, China
Undergraduate Degree:
Nankai University, Tianjin, China
Research Synopsis:
POT1 (protection of telomeres 1) is a single-strand telomeric DNA binding protein that in yeast and mammals plays an important role in telomere length regulation and chromosome end protection. Interestingly, there are two highly divergent POT1-like genes in Arabidopsis thaliana, AtPOT1a and AtPOT1b. In striking contrast to the situation in yeast and mammals, disruption of AtPOT1a in Arabidopsis leads to progressive telomere shortening, but chromosome ends, at least initially, remain fully protected. Thus, AtPOT1a has evolved the specialized function of serving as a positive regulator of telomere length. Supporting this conclusion, biochemical data indicate that AtPOT1a is an accessory subunit of the telomerase RNP complex that only transiently associates with telomeres during S-phase when telomerase is known to act.
To dissect the functional domains in AtPOT1a, a genetic complementation analysis was undertaken. To exaggerate the differences in telomere length between pot1a mutants and wild type plants, we crossed pot1a into a genetic background where telomeres undergo dramatic elongation in an AtPOT1a-dependent manner. We are now utilizing this complementation system to understand functional domains in AtPOT1a and POT1 gene evolution in plants by cross species complementation experiments.