Ricerc@Sapienza

Telomere maintenance is a key molecular process required to prevent cell senescence. Impairment of telomere maintenance results into severe diseases such as Dyskeratosis Congenita (DC), on the other hand aberrant activation of the telomere elongation allows cancer cells to escape senscence.
Telomerase is the key enzyme involved in telomere maintenance. This enzyme consists of a protein component (TERT) and a non-coding RNA moiety (TERC). TERC maturation is a key step in the assembly of a functional telomerase enzyme and requires DKC1 (a gene whose loss is causative of DC) and PARN (a polyA ribonuclease previously involved in small RNA biogenesis). Our preliminary data show that not only AGO2 interacts with DKC1, TERC and a small RNA derived from the 3' end of TERC (sm-TERC-RNA), but also that AGO2 depletion reduces telomere length, telomerase activity and clonogenicity of human cells. We therefore hypothesize that AGO2 might take part in TERC processing.
The proposed project aims at elucidating the molecular mechanisms through which AGO2, DKC1, PARN and a sm-TERC-RNA contribute to TERC maturation to ensure proper telomerase function. We will check by means of biochemical purifications the interactions between AGO2, TERC, PARN and DCK1, we will investigate which of these factors are involved in sm-TERC-RNA biogenesis by gene silencing/overexpression approaches in cell lines. We expect to clarify the role played by AGO2 and sm-TERC RNA in TERC maturation and identify molecular strategies to modulate telomerase activity which might be exploited to target cancer cells as well as to ameliorate life quality of DC patients.