Molecular mechanism of telomere protection by telomerase

Telomeres are the protein-DNA complexes at the ends of linear chromosomes; they are required for the genome integrity and chromosome stability. Telomeres could be elongated by the telomerase or by homologous recombination in the absence of telomerase.

 

In the budding yeast Sacchromyces cerevisiae, the telomerase holoenzyme contains the catalytic subunit Est2, RNA template Tlc1 and the regulatory subunits Est1 and Est3. Previous studies by Dr. Jin-Qiu Zhou’s group (SIBCB, SIBS, CAS), which was published in Nature Structural & Molecular Biology, revealed that Est1 could promote telomeric single-stranded DNA to form G-quadruplex structure, which is required for telomere replication. Their further studies found that the G-quadruplex promoting activity of Est1 is essential for telomere protection and inhibition of telomere recombination. Their results were published in Molecular and Cellular Biology electronically ahead of print on 10th of January. These studies demonstrate that Est1 promotes telomeric G-quadruplex formation, which play dual roles in telomere replication and telomere protection.

 

This work was supported by grants from the Ministry of Science and Technology of China and the National Natural Science Foundation of China.